A bookmark is the simplest form of learner annotation: a saved video timestamp, optionally paired with a short user-supplied label, that the learner can click to jump directly to that moment in a subsequent session without rewinding. Bookmarks are stored server-side against the learner's account and the video identifier, which distinguishes them from browser-level mechanisms and ensures they persist across devices and sessions. They differ from chapter markers in origin and granularity: chapters are author-defined, coarse-grained structural divisions, while bookmarks are learner-defined, arbitrary-precision markers that can be placed at any second of the video. Bookmarks reduce the friction of returning to review material, which supports spaced-repetition workflows where a learner deliberately re-watches difficult segments days after the initial viewing. In cohort settings, bookmarks can be made visible to a cohort or instructor — a shared bookmark list surfaces moments the group found worth noting, functioning as a lightweight social curation layer. From an xAPI perspective, bookmark creation maps naturally to a custom "bookmarked" verb with the video identifier and timestamp in the object and context; xAPI Video Profile does not define a bookmark verb, so platforms use a custom extension. The main design consideration is discoverability: if the bookmark button is buried in a secondary menu, learners will not use it, and the feature adds no learning value; placement alongside the progress bar or a keyboard shortcut is the standard solution.
