Here are over 200 services that can bookmark and share! This without counting the +250 digg clones!
What's so great about SOCIAL bookmarks is that it creates a people powered search engine. Even if you don't use these services to bookmark you can use these for searching, the more a web page is bookmarked the more popular!

Used on some Blogsites to assist folks in posting to their favorite Social Bookmarking site such as delicious, fark, magnolia, and PennTags!

A very very long annotated list of social bookmarking sites.