only the first 500 will be listed in bold on your Friends list and appear on your Mutual Friends list
"Friends" should be "Friend Of" -- the friends list isn't bolded. (Well, not for the logged-in user viewing their own userinfo page, at any rate, and other users wouldn't be affected by the 500 limit thing.) --and does the 500-user limit apply to them viewing another user's userinfo page? (i.e. if I have 510 users on my friends list, and I go to someone's userinfo page and they have 10 friends in common with me, would those necessarily be bold, or would they be not bold if they're the unlucky 10 that don't get checked?)
Also, I kind of want to say that the "and" should be an "or", since it won't simultaneously affect FO list bolding and the Mutual Friends list, but I'm less caring about that one. :)
(And really, while this whole FAQ contains fragments of information that can be individually useful, it is also horrendously disorganized and kind of icky. It needs, like, sorting or organizing or something. *twitch* But that's another matter entirely.)