Statistics are like buses: none are released for ages and then suddenly loads come at once. Or that’s how it seems this week, with new data on the user numbers for Facebook, Twitter, Google+ and YouTube.

So here we go:

YouTube announces that over 800 million unique visitors come to its site every month. That and lots of other juicy stats can be found here, or read Mashable’s take here.

Mashable also announces that Facebook Now Has 901 Million Users, which seems a dazzling amount. Read the scoop here, as it also contains the factoid that Twitter has 140 million active users. Phew.

More Twitter info from a graphic on The Wall Blog. Some interesting stats here, including the one that surprised me, namely that the country with the second largest group of Twitter users is Brazil. See the graphic for yourself, here.

Bringing up the rear, Google+ has tweaked its design of late and now boasts 170 million users. This article from The Wall Blog gives the skinny on that, plus a lot of other very useful info about the site’s features. Here’s the article. Mashable also cites a study which claims that March saw a rise in Google+ users of 27%… read it here.

Is your organisation one of these users? Tell us about how you use social media by taking part in my UK Social Media study!