Since opening up invite-free to the public, it's been Google+ mania. You can't walk down the street without hearing someone exclaiming their joy that yet another social network has entered their life. Or something like that.

Whether its cultural impact is on a par with other social platforms is debatable at the moment, but as Pocket-lint's teacher said the day we were relieved of our milk money collecting duties - "the figures don't lie".

And the figures are big: 50 million big according to Paul Allen, who has been tracking Google+ users from day one.

"Since being opened to the general public (over age 18) last week, Google+ has been growing by at least 4 per cent per day, meaning that around 2 million new users have been signing up each day," he wrote, on Google+ of course.

Although well behind Zuckerberg Industries' 800 million users, Facebook took almost 4 years to hit the 50 million figure, and Twitter took 3 years.

And what can those 50 million +ers expect except for Hanging Out or Huddling? How's about a spot of the massively popular Zynga title CityVille, a Facebook favourite don't forget, which has spread its wings and is now available on the Big G's network.

"It’s no secret we’re big fans of Google+ here at Zynga," stated a blog post. "Last month we announced that we partnered with Google to bring Zynga Poker to Google+, and today we’re excited to add CityVille+ to the new game platform.

"CityVille grew to become our largest game on Facebook, so naturally we wanted to 'build' a presence for it on Google+. Ultimately, we want to make our games accessible to everyone, everywhere - no matter where they play or what platform they play on."

Google invested between $100 million and $200 million in the company back in 2010. No wonder it's such a big fan.