From Seo Wiki - Search Engine Optimization and Programming Languages
tag|Connect is an Intelink-based bookmark tool based loosely on del.icio.us. It combines traditional bookmarking with a community, so that users can see and search each other's bookmarks, comment on them, and organize them by flat, non-hierarchical categories called "tags."
At first, this system appears to be just another way of bookmarking pages. However, upon further use, users will begin to see the value of sharing their bookmarks and exploring others'. For example, they will find users whose tastes are similar to their own, and thereby find web pages of interest that they otherwise would not have found—users with similar interest are acting as your search engine. Social bookmarking also cuts down on email because it reduces the number "hey, did you see this link" emails.