Active accounts have become one of the hottest currencies online, especially for social networks. Previous boasts by Facebook have been quickly shot down, but this latest number is pretty hard to ignore. According to Zuckerberg himself the site now has 1 billion active monthly users. That's right, one in seven people on the planet logs on to the social network at least once a full moon cycle. The announcement comes via the site's official news blog, which if the numbers are true, could mean most of you have read this already. Zuckerberg broke the news originally in a Q&A with Bloomberg Businessweek, also claiming that the site now has 600 million mobile users.