I hit a limit today:
Looks like I have to dig back through my old faves and remove ones that aren't so favey. There are at least two obstacles in my way, however:
- Notice how it says I have "(502 videos)" in my favorites? How's that even possible?
- I've wished for a long time that favorites could be sorted into folders. You can create playlists, but I've found their behavior to be flakey. YouTube provides a "Next" button for advancing to further pages, but there's no "End" button that allows me to get to the very end of the list.
So, there's a lot of paging to be done.I did later notice I could edit the URL to get all the way to… http://youtube.com/my_favorites?page=51
Ah well, might as well clean up. 
{ 3 comments… read them below or add one }
What? I have only 20-30 favorites! O.O
Hmm, sounds like one of those things to take into your own hands. Just like I'm now creating a page with my fav places in SL (using SLurls), in categories and with a photo of each place, you could make a page (or wiki!) with fav YouTube videos and thumbnails.
Btw, there's a free wiki host at http://pbwiki.com/ (but I don't know the limitations for a free account, you can buy more storage though).
@Daedalus: It's a good idea; I of course would like to be able to automate the process, because I'm sure that adding many more YouTube favorites would have be looking for ways to cut down any manual steps involved in an external workaround. Apparently, tho, you can keep adding vids to new YouTube playlists to get around the 500 favorites issue… which doesn't make much sense to me. Google should just offer unlimited faves, unless it's particularly "expensive" for some technical reason.