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".
Let me tell you about John. John is a great guy. A good Doctor. A loving husband and a great Father. John is all these things and more. But one tiny detail, not evident. Not immediately. John believes the earth is flat. John absolutely believes the world is flat.
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.
Fingers crossed this is a prelude to what I like to call "Google Galaxy", where you can zoom all the way out and see the entirety of the Milky Way. A man can dream.