http://en.support.wordpress.com/avatars/blavatars/
"A Blavatar is an image associated with a blog. It will be displayed as the favicon for your blog, which shows up in a browser’s address bar and on browser tabs. It will show up in the comments section of a blog if you send out any pingbacks. If anyone create a shortcut to your blog on their iPhone it will also be used as the icon there."
Mir geht es vor allem um den zweiten Teil mit den Pingbacks etc.