Note: Access to this feature via a link has been (temporarily?) removed from BGG.
You can still access it by entering this into your browser's address bar:
Your Personal Recommendations is a list of games the BGG software thinks you might enjoy. They are based on the ratings you have given to other games.
A link to Personal Recommendations is on My Geek.
There are other ways to find games you like. See "How do I find other games similar to the games I already know and like?" in BoardGameGeek FAQ.