Think of #isms as a filter on the wider porn caption caption archive: same submission pool, but slimmed down to the exact register you searched for.
The internal-link graph around #isms is dense on purpose: related tags at the top, most-viewed further down, and every card links out to its own individual post page with its own share preview.
Because #isms 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 #isms archive rewards repeat trips — the top of the grid tomorrow won't be identical to today.
Every #isms post is a standalone URL with its own share preview, alt text and interaction counts.