Take an intuitive design, easy navigation, put everything *right there* and make it easy to import your saved links at del.icio.us and Furl and what do you get?

Blinklist!

Blinklist has all the usabilty of Technorati but concentrates on individual URLs instead of blogs. It uses a Google-esque approach to design: lots of white, very clean and is even labeled "beta".

There are features galore with this site and I would definately call it an up-and-comer. Not only can you mark "friends" you can also become a "fan". One of the best features is when you search for a KW the tags that have been applied to the URL in that catagory are listed in a drop-down menu. This means a search for [seo] has subcatagories of search, google, marketing, tools... I can't think of an easier way to narrow a search on your terms.

Watch out for this one - I predict it will be huge.