I agree it's very similar and it could be annoying but..
If I were you I wouldn't be supprised that many take example by you. When people think of success in this biz they put it together with your site and try to follow your path (also subconsciously). Some will do it pretty similar to your site but unless he is not stealing your code, using same keyworlds (especially related to name/brand of your site) and pretend to be you I belive you have to accept it.. and be proud of it
He stole you piece of your personality but the might of your site is, as I suppose, in your quality trades, bookmarkers, and tons of backlinks..