Facebook now has 150m active users

"Today, we reached another milestone: 150 million people around the world are now actively using Facebook and almost half of them are using Facebook every day. This includes people in every continent—even Antarctica. If Facebook were a country, it would be the eighth most populated in the world, just ahead of Japan, Russia and Nigeria.
When we first started Facebook almost five years ago, most of the people using it were college students in the United States. Today, people of all ages—grandparents, parents and children—use Facebook in more than 35 different languages and 170 countries and territories."
Source: Mark Zuckerberg, writing in the Facebook blog, 7th January 2008