Flat maps are so 7000 BC. With modern computers, we have the technology to render the world in its true form (ignoring conspiracies): a globe. Or oblate spheroid, if you prefer. Which is why it's a surprise it took Google this long to adopt a rotatable, third-dimension for Maps.
There's nothing on Google's official blog for Maps that mentions the change, which could suggest it's still in testing. Not that there's much to test — it doesn't really add much to the site's functionality, other than coolness and the thing is still called "Google Maps".
At first I thought it might be a two-stage thing, switching from 2D to 3D when you zoom out far enough, but if you look carefully, you'll sense a "globe-ness" when you navigate around regardless of distance, which suggests it's permanently 3D.
Gizmodo Australia is gobbling up the news in a different timezone, so check them out if you need another Giz fix.