Social and Short-Form Glossary · UGC Platforms

Affiliate attribution window: how long after a view or click an order can still credit a creator; clicks take precedence over views (Social Commerce & Live Shopping).
Appearance effect: an effect that reshapes or resizes facial or body features or alters skin; flagged per version so it can be restricted for minors, disclosed and labeled (Camera & Effects).
Audience snapshot: the audience of an ephemeral item as it stood when posted: the base (public, followers, friends, a list or named recipients) and the resolved accounts for lists, kept so later list edits can narrow who sees it but never widen it (Stories & Disappearing Content).
BIPA (Biometric Information Privacy Act): Illinois' law requiring written notice, a written release and a public retention schedule before collecting biometrics, with $1,000 or $5,000 liquidated damages and, since August 2024, one recovery per person (Camera & Effects).
Biometric consent: a per-feature, per-jurisdiction record of the notice shown, the release given, the retention term and when face data was destroyed, needed only for features that keep face data off the device (Camera & Effects).
Brushing: fake orders from fake accounts to real addresses, shipped with cheap items, to post verified-buyer reviews (Social Commerce & Live Shopping).
Capture credentials: a C2PA manifest the capturing app signs at capture or publish, describing the capture and the effects applied, as Pixel Camera does for every JPEG (Camera & Effects).
Capture source: whether a post's media was recorded in the platform's camera, imported from the device library, exported from an editor or sent by API; a client claim kept on the media asset (Camera & Effects).
Close Friends list: a private list only its owner can see and nobody can ask to join, used as the audience for Stories, Notes and Instants; being on one is sensitive data (Stories & Disappearing Content).
Closed-loop commerce: a platform runs the catalog, checkout, payment and often fulfilment, so it sees and is liable for every order; the opposite is link-out commerce (Social Commerce & Live Shopping).
Collisionless embedding table: an embedding store (Monolith uses a cuckoo hashmap) that gives every id its own row instead of hashing ids into shared rows, with admission thresholds and expiry to bound memory (Interest-Graph Feeds).
Commercial music library: a pre-cleared catalog for business accounts and ads, separate from the general library licensed for personal use only (TikTok's Commercial Music Library, Meta's Sound Collection) (Sounds, Remix & Duets).
Content-led commerce: buying that starts from a video, post or live stream rather than a search, often crediting the creator who drove it (Social Commerce & Live Shopping).
Counter bid time: the time a live auction resets to when a bid arrives near the end, so other bidders can respond (Social Commerce & Live Shopping).
CUBI (Capture or Use of Biometric Identifier Act): Texas' biometric law, requiring consent before capture and destruction within a year of the purpose ending, with penalties up to $25,000 per violation enforced by the attorney general (Camera & Effects).
Daily prompt: BeReal's once-a-day notification at a random time, with two minutes to post a front-and-back camera photo, a "late" label afterwards and friends' posts visible only after posting; copied by Instagram's Candid Stories and TikTok Now (Stories & Disappearing Content).
De minimis exemption: the US rule that let shipments of $800 or less enter duty-free; suspended for all countries from August 29, 2025, with the statute ending July 1, 2027 (Social Commerce & Live Shopping).
Deal lapse: a licensor agreement expiring unrenewed, which mutes every use of every sound that depends on it, including songs it only co-publishes, as in the 2024 UMG and TikTok dispute (Sounds, Remix & Duets).
Deep Retrieval: ByteDance's learned retrieval index, which maps each item to several paths through a layered structure trained with an EM-style algorithm, and serves candidates by beam search instead of nearest-neighbor search (Interest-Graph Feeds).
Disappearing messages: a conversation-level timer (WhatsApp's 24 hours, 7 days or 90 days; Snapchat's after viewing, 24 hours or 7 days after viewing, or never) that governs each message by the setting in force when it was sent (Stories & Disappearing Content).
Dispersal rule: a mixing constraint applied after scoring, such as never showing two videos in a row from the same creator or with the same sound (Interest-Graph Feeds).
Distribution override: a recorded manual boost or demotion with a purpose, a reach cap, an expiry and a second approver, referenced from the impressions it affected (Interest-Graph Feeds).
Duet (side-by-side remix): a child post that plays the whole parent video at the same time as its own, in a layout (Sounds, Remix & Duets).
Early skip: a viewer swiping away within the first few seconds (Instagram's Reels card predicts under three seconds); noisy for one viewer, a strong negative signal across many (Interest-Graph Feeds).
Effect: a real-time camera program (overlay, distortion, tracking or generative rewrite) that a platform or an outside creator publishes, reviewed and served by version (Camera & Effects).
Effect attribution: the record of which effect versions made a post, written by the client at capture and validated by the server; it drives effect pages, creator rewards and takedown sweeps (Camera & Effects).
Effect creator rewards: incentive pay to effect creators based on distinct public posts within a window after launch, such as TikTok's Effect Creator Rewards and Snap's Lens Creator Rewards (Camera & Effects).
Effect page: an effect's public page with its creator and the posts that used it, a query over attribution (Camera & Effects).
Effect runtime: the sandbox in the platform's camera that runs third-party effect scripts and assets against tracking results, with no network by default and hard memory and frame-time limits (Camera & Effects).
Effect version: an immutable, separately reviewed package of an effect; posts record the version that made them, and a failed update leaves the previous approved version live (Camera & Effects).
Expiry versus deletion versus purge: stopping serving to the audience, removal from the product, and destruction of every copy the platform controls; three events with three clocks that a platform must not describe as one (Stories & Disappearing Content).
Face geometry: the term Illinois' BIPA ("scan of hand or face geometry") and Texas' CUBI ("record of hand or face geometry") use to bring face measurements under biometric law; photographs are excluded (Camera & Effects).
Feed reset: discarding a viewer's learned interest profile so recommendations restart as for a new user, while keeping their follows and explicit filters (Interest-Graph Feeds).
Frame budget: the roughly 33 ms per frame at 30 FPS in which tracking, rendering and encoding must all finish; Lens Studio requires Lenses to stay above 15 FPS on most devices (Camera & Effects).
FTC v. Snapchat (2014): the consent order over Snaps marketed as disappearing "forever" that could be saved through third-party apps, unencrypted local storage and evadable screenshot alerts; it requires a privacy program with 20 years of biennial independent audits (Stories & Disappearing Content).
Generative recommender: a model that treats a user's history of actions as a sequence and produces the next items directly, such as Meta's HSTU and Kuaishou's OneRec, replacing part or all of the retrieval-and-ranking cascade (Interest-Graph Feeds).
Ghost Mode: Snap Map's timed hiding of a user's location from everyone (3 hours, 24 hours or until turned off), which still shares the location with Snap and doesn't hide map submissions (Stories & Disappearing Content).
Grace window: the documented gap between an item's expiry and its purge, when it serves to no one but can still be reported and attached to a case (Stories & Disappearing Content).
Green screen remix: the parent's video used as the backdrop behind the child's recording (Sounds, Remix & Duets).
Heating: TikTok's practice, reported by Forbes in January 2023, of staff manually boosting chosen videos into For You feeds to reach a target number of views (Interest-Graph Feeds).
Highlight: expired Stories collected on a profile until removed; each item keeps its original audience snapshot, so a highlight never widens it (Stories & Disappearing Content).
Implied truth effect: Google's term for viewers assuming unlabeled content is "not AI" when only synthetic content carries a label (Camera & Effects).
Interest-graph feed: a feed whose candidates come from any eligible item, chosen by predicted interest rather than by follows, so new viewers and new creators get distribution from the first session and the first post (Interest-Graph Feeds).
Late dispatch rate: the share of orders not handed to a carrier by their computed dispatch deadline (Social Commerce & Live Shopping).
License scope: the (sound, territory, account kind, surface, length, time) tuple a music feature checks, answered from the deals behind every recording owner and composition share (Sounds, Remix & Duets).
Live offer: a price, allocated quantity, per-buyer limit and server-time window for a product inside one live sale, separate from the listing (Social Commerce & Live Shopping).
Multi-task ranker: one model with an output per predicted action (like, share, finish, skip, hide, report, watch time), whose outputs a value model folds into one score (Interest-Graph Feeds).
Online training: updating a recommendation model continuously from a joined stream of served features and user actions, so serving embeddings are minutes old rather than a day old (Interest-Graph Feeds).
Open affiliate plan: a seller's standing commission offer to any eligible creator, for a product or the whole shop (Social Commerce & Live Shopping).
Original sound: audio extracted from a user's upload and made reusable under their name; not cleared just because a user made it, so it is matched against the catalog before it gets a page (Sounds, Remix & Duets).
Pattern interruption: a limit across a session on how many recent items come from one sensitive topic cluster (sadness, extreme dieting), enforced by substituting other topics (Interest-Graph Feeds).
Purge ledger: one row per kind of copy (origin, variants, CDN, search, derived features, receipts, backup) per expired item, proving it was destroyed everywhere the platform controls (Stories & Disappearing Content).
Qualified divestiture: under the US TikTok divestiture law, a transaction the President determines ends foreign-adversary control and any operational relationship with the former owner, including cooperation on the content recommendation algorithm (Interest-Graph Feeds).
Re-attribution: changing a sound's credit from the originator to a matched catalog track (Instagram does it automatically), recorded as a merge with a dispute path (Sounds, Remix & Duets).
Recommendation eligibility: whether a published item may be recommended to strangers (eligible, ineligible, adults only, limited), a state separate from removal, with a reason, a policy version and an appeal path (Interest-Graph Feeds).
Remix edge: the record linking a child post to its parent, with shape, clipped span, layout, the permission at creation and a parent-gone policy (Sounds, Remix & Duets).
Retouched advertising label: Norway's mandatory label (in the Consumer Authority's translation, "RETOUCHED PERSON ADVERTISEMENT"), in force since July 1, 2022, for ads in which retouching or filters alter body shape, size or skin (Camera & Effects).
Reuse permission: who may duet, stitch, remix, template, download or sticker an account's posts, as an account default plus per-post overrides, locked for the youngest teens (Sounds, Remix & Duets).
Screenshot notification: telling a poster that a viewer captured their item, possible only from an OS signal that arrives after the capture (iOS) or covers only hardware-button screenshots (Android 14), and defeated by a second camera (Stories & Disappearing Content).
Seller performance score: a versioned evaluation of a seller's fulfilment and cancellation metrics that sets settlement speed, reserves and campaign access (Social Commerce & Live Shopping).
Sensitive Content Analysis: Apple's on-device nudity detection framework (iOS 17 and later), available only when the user or a parent has turned it on; apps may not send its results off the device (Camera & Effects).
Settlement tier: how many days after delivery a seller is paid, set by performance and tenure (Social Commerce & Live Shopping).
Sound: reusable audio with its own identity, attribution history, page and list of uses, separate from any one video's audio track (Sounds, Remix & Duets).
Sound page: the aggregation of every post using a sound, with the originator pinned, filtered for the viewer's country, account and blocks, and ranked like any feed (Sounds, Remix & Duets).
Stitch (sequential clip): a child post that plays a trimmed segment of the parent (up to five seconds on TikTok) before its own footage (Sounds, Remix & Duets).
Stories tray: the ranked row of authors with live Stories, ordered by unseen state and predicted affinity (Instagram's viewing history, engagement history and closeness) (Stories & Disappearing Content).
Story: a photo or short video shown to a chosen audience for about 24 hours, with no public likes, a poster-only viewer list and replies sent as direct messages; Snapchat 2013, Instagram 2016 (Stories & Disappearing Content).
Sudden death auction: a live auction with no end-of-auction extension; the highest bid before zero wins (Social Commerce & Live Shopping).
Synthetic voice: a text-to-speech or voice-effect voice, licensed like talent with a consent scope and a retirement date (Sounds, Remix & Duets).
Targeted affiliate plan: a commission or flat-fee offer to named creators for a period, whose rate supersedes the open plan's (Social Commerce & Live Shopping).
Template: reusable slot timings against a sound, filled with the child's own clips; it inherits the sound's license scope (Sounds, Remix & Duets).
Tryout round: one stage of a new post's staged distribution: a sized audience, metrics against peer videos, then a decision to widen, hold, stop or send to review (Interest-Graph Feeds).
View once: media that disappears after each recipient opens it once (Snaps, WhatsApp View Once, Instagram Instants); the asset can't be purged until every recipient has opened it or the unopened ceiling passes (Stories & Disappearing Content).
Wash trading (GMV): a seller or creator buying their own products through linked accounts to inflate sales, tiers or commissions (Social Commerce & Live Shopping).
Watch ratio: time watched on the first pass divided by the video's length, compared against videos of the same length, so that short and long videos can be ranked on the same footing (Interest-Graph Feeds).

Affiliate attribution window: how long after a view or click an order can still credit a creator; clicks take precedence over views (Social Commerce & Live Shopping).
Appearance effect: an effect that reshapes or resizes facial or body features or alters skin; flagged per version so it can be restricted for minors, disclosed and labeled (Camera & Effects).
Audience snapshot: the audience of an ephemeral item as it stood when posted: the base (public, followers, friends, a list or named recipients) and the resolved accounts for lists, kept so later list edits can narrow who sees it but never widen it (Stories & Disappearing Content).
BIPA (Biometric Information Privacy Act): Illinois' law requiring written notice, a written release and a public retention schedule before collecting biometrics, with $1,000 or $5,000 liquidated damages and, since August 2024, one recovery per person (Camera & Effects).
Biometric consent: a per-feature, per-jurisdiction record of the notice shown, the release given, the retention term and when face data was destroyed, needed only for features that keep face data off the device (Camera & Effects).
Brushing: fake orders from fake accounts to real addresses, shipped with cheap items, to post verified-buyer reviews (Social Commerce & Live Shopping).
Capture credentials: a C2PA manifest the capturing app signs at capture or publish, describing the capture and the effects applied, as Pixel Camera does for every JPEG (Camera & Effects).
Capture source: whether a post's media was recorded in the platform's camera, imported from the device library, exported from an editor or sent by API; a client claim kept on the media asset (Camera & Effects).
Close Friends list: a private list only its owner can see and nobody can ask to join, used as the audience for Stories, Notes and Instants; being on one is sensitive data (Stories & Disappearing Content).
Closed-loop commerce: a platform runs the catalog, checkout, payment and often fulfilment, so it sees and is liable for every order; the opposite is link-out commerce (Social Commerce & Live Shopping).
Collisionless embedding table: an embedding store (Monolith uses a cuckoo hashmap) that gives every id its own row instead of hashing ids into shared rows, with admission thresholds and expiry to bound memory (Interest-Graph Feeds).
Commercial music library: a pre-cleared catalog for business accounts and ads, separate from the general library licensed for personal use only (TikTok's Commercial Music Library, Meta's Sound Collection) (Sounds, Remix & Duets).
Content-led commerce: buying that starts from a video, post or live stream rather than a search, often crediting the creator who drove it (Social Commerce & Live Shopping).
Counter bid time: the time a live auction resets to when a bid arrives near the end, so other bidders can respond (Social Commerce & Live Shopping).
CUBI (Capture or Use of Biometric Identifier Act): Texas' biometric law, requiring consent before capture and destruction within a year of the purpose ending, with penalties up to $25,000 per violation enforced by the attorney general (Camera & Effects).
Daily prompt: BeReal's once-a-day notification at a random time, with two minutes to post a front-and-back camera photo, a "late" label afterwards and friends' posts visible only after posting; copied by Instagram's Candid Stories and TikTok Now (Stories & Disappearing Content).
De minimis exemption: the US rule that let shipments of $800 or less enter duty-free; suspended for all countries from August 29, 2025, with the statute ending July 1, 2027 (Social Commerce & Live Shopping).
Deal lapse: a licensor agreement expiring unrenewed, which mutes every use of every sound that depends on it, including songs it only co-publishes, as in the 2024 UMG and TikTok dispute (Sounds, Remix & Duets).
Deep Retrieval: ByteDance's learned retrieval index, which maps each item to several paths through a layered structure trained with an EM-style algorithm, and serves candidates by beam search instead of nearest-neighbor search (Interest-Graph Feeds).
Disappearing messages: a conversation-level timer (WhatsApp's 24 hours, 7 days or 90 days; Snapchat's after viewing, 24 hours or 7 days after viewing, or never) that governs each message by the setting in force when it was sent (Stories & Disappearing Content).
Dispersal rule: a mixing constraint applied after scoring, such as never showing two videos in a row from the same creator or with the same sound (Interest-Graph Feeds).
Distribution override: a recorded manual boost or demotion with a purpose, a reach cap, an expiry and a second approver, referenced from the impressions it affected (Interest-Graph Feeds).
Duet (side-by-side remix): a child post that plays the whole parent video at the same time as its own, in a layout (Sounds, Remix & Duets).
Early skip: a viewer swiping away within the first few seconds (Instagram's Reels card predicts under three seconds); noisy for one viewer, a strong negative signal across many (Interest-Graph Feeds).
Effect: a real-time camera program (overlay, distortion, tracking or generative rewrite) that a platform or an outside creator publishes, reviewed and served by version (Camera & Effects).
Effect attribution: the record of which effect versions made a post, written by the client at capture and validated by the server; it drives effect pages, creator rewards and takedown sweeps (Camera & Effects).
Effect creator rewards: incentive pay to effect creators based on distinct public posts within a window after launch, such as TikTok's Effect Creator Rewards and Snap's Lens Creator Rewards (Camera & Effects).
Effect page: an effect's public page with its creator and the posts that used it, a query over attribution (Camera & Effects).
Effect runtime: the sandbox in the platform's camera that runs third-party effect scripts and assets against tracking results, with no network by default and hard memory and frame-time limits (Camera & Effects).
Effect version: an immutable, separately reviewed package of an effect; posts record the version that made them, and a failed update leaves the previous approved version live (Camera & Effects).
Expiry versus deletion versus purge: stopping serving to the audience, removal from the product, and destruction of every copy the platform controls; three events with three clocks that a platform must not describe as one (Stories & Disappearing Content).
Face geometry: the term Illinois' BIPA ("scan of hand or face geometry") and Texas' CUBI ("record of hand or face geometry") use to bring face measurements under biometric law; photographs are excluded (Camera & Effects).
Feed reset: discarding a viewer's learned interest profile so recommendations restart as for a new user, while keeping their follows and explicit filters (Interest-Graph Feeds).
Frame budget: the roughly 33 ms per frame at 30 FPS in which tracking, rendering and encoding must all finish; Lens Studio requires Lenses to stay above 15 FPS on most devices (Camera & Effects).
FTC v. Snapchat (2014): the consent order over Snaps marketed as disappearing "forever" that could be saved through third-party apps, unencrypted local storage and evadable screenshot alerts; it requires a privacy program with 20 years of biennial independent audits (Stories & Disappearing Content).
Generative recommender: a model that treats a user's history of actions as a sequence and produces the next items directly, such as Meta's HSTU and Kuaishou's OneRec, replacing part or all of the retrieval-and-ranking cascade (Interest-Graph Feeds).
Ghost Mode: Snap Map's timed hiding of a user's location from everyone (3 hours, 24 hours or until turned off), which still shares the location with Snap and doesn't hide map submissions (Stories & Disappearing Content).
Grace window: the documented gap between an item's expiry and its purge, when it serves to no one but can still be reported and attached to a case (Stories & Disappearing Content).
Green screen remix: the parent's video used as the backdrop behind the child's recording (Sounds, Remix & Duets).
Heating: TikTok's practice, reported by Forbes in January 2023, of staff manually boosting chosen videos into For You feeds to reach a target number of views (Interest-Graph Feeds).
Highlight: expired Stories collected on a profile until removed; each item keeps its original audience snapshot, so a highlight never widens it (Stories & Disappearing Content).
Implied truth effect: Google's term for viewers assuming unlabeled content is "not AI" when only synthetic content carries a label (Camera & Effects).
Interest-graph feed: a feed whose candidates come from any eligible item, chosen by predicted interest rather than by follows, so new viewers and new creators get distribution from the first session and the first post (Interest-Graph Feeds).
Late dispatch rate: the share of orders not handed to a carrier by their computed dispatch deadline (Social Commerce & Live Shopping).
License scope: the (sound, territory, account kind, surface, length, time) tuple a music feature checks, answered from the deals behind every recording owner and composition share (Sounds, Remix & Duets).
Live offer: a price, allocated quantity, per-buyer limit and server-time window for a product inside one live sale, separate from the listing (Social Commerce & Live Shopping).
Multi-task ranker: one model with an output per predicted action (like, share, finish, skip, hide, report, watch time), whose outputs a value model folds into one score (Interest-Graph Feeds).
Online training: updating a recommendation model continuously from a joined stream of served features and user actions, so serving embeddings are minutes old rather than a day old (Interest-Graph Feeds).
Open affiliate plan: a seller's standing commission offer to any eligible creator, for a product or the whole shop (Social Commerce & Live Shopping).
Original sound: audio extracted from a user's upload and made reusable under their name; not cleared just because a user made it, so it is matched against the catalog before it gets a page (Sounds, Remix & Duets).
Pattern interruption: a limit across a session on how many recent items come from one sensitive topic cluster (sadness, extreme dieting), enforced by substituting other topics (Interest-Graph Feeds).
Purge ledger: one row per kind of copy (origin, variants, CDN, search, derived features, receipts, backup) per expired item, proving it was destroyed everywhere the platform controls (Stories & Disappearing Content).
Qualified divestiture: under the US TikTok divestiture law, a transaction the President determines ends foreign-adversary control and any operational relationship with the former owner, including cooperation on the content recommendation algorithm (Interest-Graph Feeds).
Re-attribution: changing a sound's credit from the originator to a matched catalog track (Instagram does it automatically), recorded as a merge with a dispute path (Sounds, Remix & Duets).
Recommendation eligibility: whether a published item may be recommended to strangers (eligible, ineligible, adults only, limited), a state separate from removal, with a reason, a policy version and an appeal path (Interest-Graph Feeds).
Remix edge: the record linking a child post to its parent, with shape, clipped span, layout, the permission at creation and a parent-gone policy (Sounds, Remix & Duets).
Retouched advertising label: Norway's mandatory label (in the Consumer Authority's translation, "RETOUCHED PERSON ADVERTISEMENT"), in force since July 1, 2022, for ads in which retouching or filters alter body shape, size or skin (Camera & Effects).
Reuse permission: who may duet, stitch, remix, template, download or sticker an account's posts, as an account default plus per-post overrides, locked for the youngest teens (Sounds, Remix & Duets).
Screenshot notification: telling a poster that a viewer captured their item, possible only from an OS signal that arrives after the capture (iOS) or covers only hardware-button screenshots (Android 14), and defeated by a second camera (Stories & Disappearing Content).
Seller performance score: a versioned evaluation of a seller's fulfilment and cancellation metrics that sets settlement speed, reserves and campaign access (Social Commerce & Live Shopping).
Sensitive Content Analysis: Apple's on-device nudity detection framework (iOS 17 and later), available only when the user or a parent has turned it on; apps may not send its results off the device (Camera & Effects).
Settlement tier: how many days after delivery a seller is paid, set by performance and tenure (Social Commerce & Live Shopping).
Sound: reusable audio with its own identity, attribution history, page and list of uses, separate from any one video's audio track (Sounds, Remix & Duets).
Sound page: the aggregation of every post using a sound, with the originator pinned, filtered for the viewer's country, account and blocks, and ranked like any feed (Sounds, Remix & Duets).
Stitch (sequential clip): a child post that plays a trimmed segment of the parent (up to five seconds on TikTok) before its own footage (Sounds, Remix & Duets).
Stories tray: the ranked row of authors with live Stories, ordered by unseen state and predicted affinity (Instagram's viewing history, engagement history and closeness) (Stories & Disappearing Content).
Story: a photo or short video shown to a chosen audience for about 24 hours, with no public likes, a poster-only viewer list and replies sent as direct messages; Snapchat 2013, Instagram 2016 (Stories & Disappearing Content).
Sudden death auction: a live auction with no end-of-auction extension; the highest bid before zero wins (Social Commerce & Live Shopping).
Synthetic voice: a text-to-speech or voice-effect voice, licensed like talent with a consent scope and a retirement date (Sounds, Remix & Duets).
Targeted affiliate plan: a commission or flat-fee offer to named creators for a period, whose rate supersedes the open plan's (Social Commerce & Live Shopping).
Template: reusable slot timings against a sound, filled with the child's own clips; it inherits the sound's license scope (Sounds, Remix & Duets).
Tryout round: one stage of a new post's staged distribution: a sized audience, metrics against peer videos, then a decision to widen, hold, stop or send to review (Interest-Graph Feeds).
View once: media that disappears after each recipient opens it once (Snaps, WhatsApp View Once, Instagram Instants); the asset can't be purged until every recipient has opened it or the unopened ceiling passes (Stories & Disappearing Content).
Wash trading (GMV): a seller or creator buying their own products through linked accounts to inflate sales, tiers or commissions (Social Commerce & Live Shopping).
Watch ratio: time watched on the first pass divided by the video's length, compared against videos of the same length, so that short and long videos can be ranked on the same footing (Interest-Graph Feeds).