I'm sure it is. Google obscures their involvement with Ingress by funding Niantic Labs, a "Google start-up company" that just happens to have the same address as Google's San Francisco office.

Both the Ingress website and the play store download page list "NianticLabs@Google" as the creator. Was it ever a secret? The ads were meant to be mysterious in general, but I can't remember any coverage that didn't mention the Google connection pretty prominently.

On a different note: I can't believe the game is still invite only. Do people still play it? I tried to get into it, but quickly grew tired of it because everyone around me was much better than me and I couldn't sustain the interest needed to learn the ins and outs of getting good at it.

Yeah, you are right. Google's participation is not "secret", but it's unclear (to me) how much access Google gets to Niantic Labs' user data.

Also, Ingress is "invitation only" in the sense that they will email you an invitation code if you register on their website. <:)