Google Plus debuted in BETA in June. It has seen a lot of initial hype, but as it is still in the beginning stages, it's difficult to say exactly how Google PLus will affect the Social Media landscape.
A lot of people are watching and waiting to see what the real effect, if any, will be on Facebook.
Google Plus is still seeing a huge gain in membership, which is natural for the "new kid on the block". Given that so many people already have bought into the "Google world" through Gmail accounts, and other Google partners, this is not "that" surprising. But what does it really mean numbers wise? And will it have the staying power? Will it "replace" Facebook, or work in tandem?
At this point, it looks like it's still a "stay tuned" situation. But it definitely doesn't look like it's going away anytime soon.