I ran across a reference to this site in my logfile.
From their website:
The popularity of folksonomy-driven services, along with the general acceptance of their use, has grown tremendously within the recent months. The most popular of these services focus particularly on the ‘social bookmarking’ aspect of the social networking concept. Socialmarks furthers this concept by, in addition, providing RSS and Atom feed aggregation tools (we’re currently tracking over a quarter of a million feeds)! With these features, Socialmarks also gives users the ability to tag specific feeds, a feed’s post, as well as allowing the user to add the post to their list of social bookmarks (which can also be tagged).
If you are interested in you can sign up for the beta at their site.