Google today announced that it has 135 million active users checking their Google+ streams each month, up from 100 million in mid-September. If you run the math, that means Google+ is now growing at the same pace as Facebook when it was similarly sized.

Google announced the user growth alongside a new feature called "Google+ Communities" and enhancements to Google's mobile photo app Snapseed. Its last user count update was on Sept. 17, meaning Google+ has added 35 million stream-active users in the past 2.5 months.

That means that every month Google+ is adding about 14 million stream-active users, the type of users most comparable to those on Facebook. As it happens, Facebook added monthly active users at almost the exact same pace between late August 2008, when it reached 100 million active users, and early April 2009, when it hit 200 million active users. That seven-month spurt resulted in growth of of 14.3 million users per month.

Perhaps these respectable growth numbers will help Google get back some of the respect it has lost in the social-networking space. "We launched to a lot of skepticism, and I will be the first to admit that in the wake of Orkut and Blogger and Buzz and Wave, the world had a right to be skeptical about Google," Google+ honcho Bradley Horowitz told me last week. "When we said this was different, people didn't necessarily believe us."

Now there's reason, however tenuous, to believe.