It was a magical moment when I saw the Google+ announcement. Immediately, it was obvious that Google+ is on a different scale of magnitude than Buzz, Wave, or Connect. Those were small potatoes, side projects that missed the big picture.
This is Chrome big. Maybe bigger. This might be Gmail big.
Social networking has been stagnant for several years. Since the advent of Twitter, there have been no new major players to speak of. Facebook is relying heavily on network effects -- people join Facebook and stay active because that's where everyone is, not because the features are fresh and useful.
The elephant in the room with social networking is that Twitter, Facebook, and pretty much everything else are built wrong for how we actually interact with each other. As everyone joined Facebook, we've ended up with "friends" representing many aspects of our lives: schools, neighborhoods, jobs, hobbies, family members. And, even though we act a little bit differently with each of these people in real life, on Facebook, we have to present the same face to everyone we know. People don't cringe because they don't want anyone to see a picture of them with an empty bottle of wine; they cringe because Facebook shows that picture to everyone.
Google+ has several potential killer apps, like nifty video chat and Instant Upload to a private album. The most important bit, though, is +Circles. Call it the killer glue that will hold everything together. The idea of +Circles is that the entire social network is built, ground-up, to let you manage your "friend" connections in groups that make sense. So, you can tell all your close friends about your night on the town and talk with your family about the reunion without cross-pollinating. This is exactly what we do in real life, and it's the part of Google+ that gives it the most potential.
Google+ is "post-Facebook". It's the next evolution of social networking.