A somewhat closed Beta will certainly generate buzz, but it can also put off a few potential users. Not everyone will be willing to click the same link several times a day in hopes that they can soon be a part of Google's inner circle.

Apparently I'm not alone in my failed attempts to join Google+.

Several commenters on a reported trouble getting into the service. That may be because the service's popularity led to a new user shutdown earlier in the week.

Google+ Project Lead Vic Gundotra announced on that the "invite mechanism" due to "insane demand."

The search giant isn't specifying what kind of numbers merit the title "insane." It did tell in a statement: "We are not sharing exact numbers on the size of the trial or who we invited. There will be enough testers involved to provide comprehensive, real-world data about how people use the product."