add recommendations based on favorites
Logged-in users can store favorites and all videos are already tagged. Since you have a 'favorites' table of user ID - video ID, simply join tables on video ID - tag ID and group by tag ID, then display in descending order of tag ID count. Once you have this count of most-favorited tags for each user, you can run a search based on multiple tags (like the existing t=blondes&t=facial and so on, but a little more complex).
Instead of simply returning all videos with these tags (which would be too many results), your search results should be ordered by how "valuable" each tag is to a particular user. For instance, if My Favorites had "facial" tags 20x and "blondes" 5x and "anal sex" 3x, a video in search results that had those three tags would get 20+5+3 "points", or 28 total. The search results should be sorted in descending order of these "points". In this way I'll see videos that are just like ones I've already favorited.
Thanks, it’s nice idea. We’ll try to realize it in future!