We discussed Google Plus here on WebRev - while it was still in a limited invitation-only beta trial. in mid-September, it opened up to the public, and saw an immediate surge in membership and traffic.
A web analyst group called Chitika published a report on Friday showing that the new social network's popularity may have been short-lived. Traffic immediately returned to beta-testing levels within a few days after the site went public (a plunge of nearly 60%). Obviously, a spike in traffic is going to occur shortly after a successful media promotional campaign and "grand opening," type hype. After a spike, there where inevitably be a fall in traffic, but a fall to the pre-opening level is a bit of a surprise.
The Chitika analysts suggest the reason for the decline may be that the site does not really provide a significant service that is not available elsewhere. They recommend an acceleration in innovation for services like the "hangouts" feature in order for the site to be successful (more on Chitika's blog).
My personal opinion is that in an attempt to become the "next Facebook," Google immediately started replicating Facebook's marketing model (which has worked for Google, too, on its search engine) by incorporating the privacy violations and other data-harvesting "features" that Facebook users find annoying at best, and unacceptable at worst. In fact, Google took things a step further, and in an effort to make sure all of its users had advertiser-worthy online purchasing credentials insisted that all of its members use the name on their drivers' licenses - even requiring documention from some and encouraging other members to rat-out anyone they knew of that was using a pseudonym. Suspected violators had their entire Google account (Gmail, photos, ect.) suspended. (See If your life is not an Open Book, Google Plus may not be for You, and Privacy is not Dead, but its hiding from Google and Facebook).
The other problem Google Plus is going to run into with trying to grow its social network is that unless it finds a way to seamlessly integrate with Facebook, it is actually going to have to pull users away from there. Facebook has over 800 million users, now, which means that everyone who wants to social network is pretty much already there. Even though they might be upset with Facebook from time to time, most don't want to go through the trouble of moving all of their pictures, notes, groups, friends, and events over from Facebook to Google Plus without a really good reason. And joining a new start-up with a reputation for flops like Google Buzz and Google Wave is not a good enough reason.
One thing is for sure. If "Google Plus" doesn't get this figured out soon, all of those "Google Minus" spoofs might not quite so funny anymore.