I just got an invite to try Flock Developer Preview, a new browser based on Gecko (the Mozilla/Firefox engine). Some of the features in Flock include:

The Blog Manager.

The Flickr Topbar.

RSS integration.

Favorites with del.icio.us integration .

The Shelf.

Will post more on this once i try all the features. Oh btw this is posted from Flock’s The Blog Manager.