Google has had this for a while now. I had noticed that development has been healthy recently. whereas before it was a relatively unnecessary tool, now it's actually useful.
if it's as useful as Google Sitemaps, then I'm happy with today's news. the protocol does look pretty similar (and by pretty similar, I mean the XML structure is virtually identical). I'm guessing porting Google Sitemaps over to this new one will be painless.
Evolution is a million line computer program falling into place by accident.