Think of #pia as a filter on the wider porn caption caption archive: same submission pool, but slimmed down to the exact register you searched for.
Score is the primary sort, freshness the secondary — meaning a #pia post from six months ago can still lead the feed if the community keeps returning to it, while brand-new drops still surface as they earn saves.
Because #pia is tag-locked, the recommendations under each post also stay in the same lane, which means fewer 'that wasn't what I wanted' clicks and more time on the actual fantasy.
Every visit reshuffles the sort weights slightly, so the same #pia archive rewards repeat trips — the top of the grid tomorrow won't be identical to today.
Every #pia post is a standalone URL with its own share preview, alt text and interaction counts.