Today, LinkedIn is announcing a pretty significant milestone. The social network for professionals has just topped 200 million members. For reference, LinkedIn hit 100 million members back in March of 2011 – meaning it’s taken them nearly two years to double their user base.

“This milestone is more than just a metric — it’s a reminder of the global footprint and the scale of impact our network has each day. Members come first at LinkedIn and we remain focused on creating economic opportunity for every professional in the world. We look forward to bringing the power of the LinkedIn network to many more professionals in the coming years,” said LinkedIn’s Deep Nishar in a blog post.

LinkedIn boasts that their 200 million users hail from over 200 countries and territories, and use the service in 19 different languages.

According to the stats, the U.S. is LinkedIn’s biggest user base – by a lot. With 74 million members, the U.S. dwarfs the next largest users base of India, which sits at 18 million members. Turkey, Colombia, and Indonesia are the countries that are growing the fastest on the network. The largest subset of LinkedIn members come from the Information Technology and Services industry.

Of course, this is a members announcement – not an active users announcement. I’ve reached out to LinkedIn for specific MAU figures, and will update this article if I hear back. It’s safe to say, however, that LinkedIn’s MAUs do not quite total 200 million.

That’s because in the world on social media, “members” or “accounts” is oftentimes a misleading metric. Take for instance Twitter, which reportedly sports over 500 million accounts. Less than half of those are active on a monthly basis, though. The latest figures put Twitter’s MAUs at 200 million.

Google+ just announced 135 million MAUs, and Facebook claims to have over 1 billion MAUs.

Here’s an infographic that LinkedIn has released in celebration of their milestone: