As we've seen with other Google services in field tests such as Google Voice, in order to receive access to Google+, Google's apparent answer to Facebook, you have to get an invite. And Google has released them to the masses. Google+ invites haven't been available to the public but now if you basically know a Google+ user, they can email you an invite and get you in the hottest new social network out there.
There's a button on the Google+ Stream page that allows users to email and invite all of their friends. It's not anything different than what we've previously seen out of Google's field tests. These invites are in high demand as the owner of this website is getting swamped with requests on Facebook as we speak. Kind of ironic.
In case you missed it, Google+ is Google's answer to the Facebook empire. It includes friend "streams," video chat (a feature Facebook should've embraced), and group texting to your friends and it's being integrated in the number one website on all the Internet. Hopefully it'll do better than Google Buzz.