Tonight in an interview Walt Mossberg and Kara Swisher at the D8 All Things Digital conference, Mark Zuckerberg, founder and CEO of Facebook, slipped out the news. Facebook now has 500 million active users, or half of a billion. It's a huge milestone for the social network. According to All Things Digital's live blog, Zuckerberg quoted the following:

When I was in college I did a lot of stupid things and I don’t want to make an excuse for that. Some of the things that people accuse me of are true, some of them aren’t. There are pranks, IMs. I started building this when I was around 19 years old, and along the way, a lot of stuff changed. We went from building a service in a dorm room to running a service that 500 million people use.

This was being on the topic of -- you guessed it -- privacy issues on Facebook. He had been questioned about if he thought it was unfair a lot of people blamed or attacked him about privacy and thinking all of our information should be made public. He somehow twisted his answer into a remarkable milestone. If "Quit Facebook Day" on Monday wasn't completely confirmed as a failure, I think it's safe to say that confirmation can now be made.