How does one get invited to this game?

I signed up a few days ago and was hoping to be invited to play by now...is there something I'm missing?

Hey bud, it's really easy to get a key because people in the beta are constantly given keys to hand out. You can PM me for one, or you can get one from somewhere else (http://www.reddit.com/r/sharedota is easiest, as as far as I know, you'll need a Steam account either way, as well as to play the game).

If you're waiting from an invite from Valve it might take awhile, when I applied not very many people where trying to get a key because it was kind of a newer thing people didn't know about, and even then it took me two months to get an invite in my mailbox.

But Jstansberry is correct, most players in the beta are given free DoTA2 invites. If you PM me your email, if you haven't already acquired an invite I can send my last one to your inbox.