At Pinterest, Closeup recommendations (aka Related Pins) is typically a feed of recommended content (primarily Pins) that we serve on any pin closeup. Closeup recommendations generate the largest amount of impressions among all recommendation surfaces at Pinterest and are uniquely critical for our users’ inspiration-to-realization journey. It’s important that we surface qualitative, relevant, and context-and-user-aware recommendations for people on Pinterest.

See also: https://group.lt/post/46301