Tags (pages/feeds), Author (pages/feeds), Source (pages/feeds), Search (pages and yes, searches have feeds too!).

It also finds similar items…so similar users are users who have recently shared the same stories. Similar stories are stories that have recently been shared by the same users.

Lastly; there is no submission page. It crawls the web looking for new accounts to add.

It also appears that as of this moment ReadBurner is not updating but RSSmeme is still chugging along.