The order the list is in, for one the API sorts: the playlists page's and a profile's. A list in an order of its own leaves it out, the followed playlists being by the date they were followed and a search's results the search's: it takes no new playlist, since the socket says neither what the user follows nor what a search matches, and moves none. Playlists already listed still change, go, and come back where they were.