Amid an intriguing ownership debacle, Facebook has reached 500 million active users. The social network's co-founder Mark Zuckerberg touted the milestone on ABC News with Diane Sawyer. In a rather awkward interview, he touched on Facebook's contentious founding, his outlook on taking the company public and the upcoming Aaron Sorkin film based on his life. Bloggers are latching onto different aspects of the interview to get a sense of where Zuckerberg is taking the popular site and what legal challenges its faces:

  • Zuckerberg Mum on a Facebook IPO, writes Jemima Kiss at The Guardian, focusing on when the company might go public:

Facebook will IPO "when it makes sense", Zuckerberg told ABC News veteran reporter Diane Sawyer, skirting any real indication of when that 'sense' might hit. Next year is generally agreed to be the target date; the Wall Street Journal reported back in March that investors anticipate a 2011 IPO valued at $35bn to $40bn. Reuters has reported that the site made $800m in revenue last year, and "tens of millions" in profit.

  • Did He Sign Away 84% of His Company?  On Tuesday, a Facebook lawyer said she was "unsure" if Zuckerberg signed a contract giving away 84% of the company to Paul Ceglia, a New York man he had worked for. Speaking with Sawyer, Zuckerberg didn't necessarily exude confidence, saying he was "quite sure" he didn't sign the document. Chris Williams at The Register finds this a little unsettling:

Note that the 26-year-old CEO isn't saying he didn't sign any contract with Ceglia--in fact his lawyers have confirmed he did--rather he's "quite sure" that what he did sign doesn't grant equity in Facebook. Ceglia's lawyers say different, and that he invested $1,000 in what became Facebook, after employing Zuckerberg to work on a separate project.

  • The Movie  Responding to questions about the upcoming film The Social Network, Zuckerberg called it "fiction" saying "people get remembered for what they build, right? People don't care about what people say about you in a movie." However, Brad McCarty at The Next Web thinks Zuckerberg is sorely mistaken:

The situation reminds me heavily of Eminem in the movie 8 Mile. While Eminem said it was a work of fiction, the movie was so close to what we all believed to be the truth that it somewhat became the truth itself. I’m firmly convinced that the same will be said of The Social Network. Partly because we don’t know the truth, and partly because we all love a good story, the movie will become the story of Zuckerberg and taken for fact, whether it is or not.