An anonymous reader writes "I project that Google will easily pass 10 million users tomorrow and could reach 20 million user by this coming weekend if they keep the Invite Button available. As one G+ user put it, it is easy to underestimate the power of exponential growth." I bet if people post in the discussion that they need invites, we can scratch each other's backs here. I've been using Google+ for a few days now (Yes I will put you in a circle and have a lot to love, but unless I can gate twitter and Facebook, the best interface in the world won't help me until I can convince my kids' grandparents to move.