Posts, a community app by Read.cv
I don't know how to feel about this new layout
I (practically) designed this. Related pins are the highest performing parts of the closeup view on Pinterest. Before, they were far below the fold and by making them more prominent, you increase engagement by (IIRC) double digit percentages.
It does seem like it's somehow still an A/B test so either they're bringing it back or they're using it for individuals who aren't very engaged.