Think of #market as a filter on the wider porn caption caption archive: same submission pool, but slimmed down to the exact register you searched for.
Every media type lives here: still caption pics, animated caption GIFs and short caption loops — so the feed doesn't force one format on you if you prefer another.
The tag's structured data (Schema.org CollectionPage + BreadcrumbList) is emitted on every render, so Google and Bing treat this as a real porn caption sub-hub rather than a query results dump.
Every visit reshuffles the sort weights slightly, so the same #market archive rewards repeat trips — the top of the grid tomorrow won't be identical to today.