Facebook Traffic Reaches Nearly 375 Million Monthly Active Users Worldwide, Led by US

Facebook said it had 350 million monthly active users (MAU) at the beginning of December. But it has been growing fast around the world since then, from what we’re seeing. Notable on today’s list: countries that are big but previously not so for Facebook are now seeing serious new growth, including Brazil, Germany and India.

The company typically updates demographic data in its advertising tool — our source — a little late. For example, we counted around 350 million at the beginning of January. Now, at the beginning of February, we’re seeing 373 million MAU across the world.

Roughly 23 million more people are using Facebook compared to 30 days ago, many in countries with big populations around the world. This is an interesting shift from much of Facebook’s international growth to date. Once Facebook began offering the service in multiple languages (it’s available in more than 70 of them as of today), it started blowing up in many countries — Canada, Iceland, Norway, South Africa, Chile, etc. — but less so in the biggest countries.

Now, a reasonably largepopulation is required to make our list of the ten fastest-growing countries by absolute audience. See below. Many countries appear to have already hit their top penetration rates — 50%, for tiny Iceland — and no longer have new users left to add.

The United States is at the top with more than 5 million new users; it also continues to be the single largest country on Facebook, with 108 million MAU. That’s 35% of the total US population.

Going down the list, we first see some regulars: Indonesia, Turkey, the United Kingdom, France. These all have been growing for many, many months. More recent arrivals are showing up, though. Mexico is on its way to becoming the largest Spanish-speaking country on Facebook; with a gain of slightly less than a million new users, it is close to the largest, Spain, Argentina and Colombia.

What do Brazil, India, Germany, The Phillipines and Mexico all have in common? Their populations have all preferred other social networks, until recently. The first two countries are Orkut strongholds, The Philippines Friendster, Germany studiVZ and other regional sites, and Mexico Hi5 and regional sites.

Overall, we expect these five countries to see the most new growth in the coming year, along with other countries that have favored Facebook’s rivals.

You can find more data details on these countries and 90 more in our monthly Global Monitor report — new version coming later this week.