Dave Winer has launched a new site "Share Your OPML".
The purpose of this site is to gather a community of subscription lists, in OPML format, and aggregate them in interesting ways.
How it works?
First, become a member of the site. Then, upload your OPML file (the list of RSS feeds to which you subscribe). After, that you can see who subscribes to the same feeds that you do, manage your feeds and many more...