Social Bookmarking Exchange (Not the standard ones)

Which Social Bookmarking sites do you use outside of the usual ones?

I know there are simply hundreds to thousands of good social bookmarking sites now and i'm trying to make my Social Exchange Site even more unique and want peoples ideas on what to add next

Reddit is a no go as the data they return always seems to throw random values. Google followlike if you want to know what ive already created as im not here to just stick links everywhere.

Craig

Ok guys Ive hand no feed back so Started Some myself

Have made the first Facebook Post Likes and Post Comments Social Exchanges ever created. We all know the benefits of likes and comments on our posts. Pushes them to the top of everyones news feed