What flock boast is that, it is a social browser. Which make it easy to use many services, which include, del.icio.us, flickr, youtube, photobucket, even facebook.
It feature a few thing like, an uploader for flickr, a blog editor(which i use to write this blog), media bar, facebook integration, which shows friends updates. web clipboard. And that is quite nifty.
the bad thing is, the interface is strange, a bit cluttered actually.
you can get flock here:
Blogged with Flock