One is worth an estimated $50bn, the other is 26 year old CEO of a company oft accused of lacking a business model, yet Microsoft’s Bill Gates and Facebook’s Mark Zuckerberg have a lot in common. At least, that what I heard from one time Fortune writer David Kirkpatrick, speaking at San Francisco’s Commonwealth Club last night about his new book, The Facebook Effect.

Introducing his book before an on-stage interview with TechCrunch founder Mike Arrington, Kirkpatrick explained that from the moment he first met Mark Zuckerberg in 2006 the then-21-year-old reminded him of Gates. “Like Microsoft, Facebook also has a vision about empowerment,” said Kirkpatrick.

While Microsoft’s was to “put a computer in every home”, he went on, Facebook’s is to create a platform to help every person on the planet meaningfully share information with every other. Each in their time is revolutionary, Kirkpatrick says. But he went on to detail similarities between the two that represent challenges to Facebook.

One is security. Is Facebook, asked an audience member, a breeding ground for scammers and other criminals? Certainly, Kirkpatrick replied. “Security is going to become problematic because it’s like Windows now, everybody wants to attack it.” With ubiquity comes the fact everyone really is out to get you.

Zuckerberg has another looming problem his older doppelganger has experienced. “I believe it will become subject to serious government regulation and push back,” Kirkpatrick says. That’s not surprising, he says, given that some of the company’s aspirations– for example to become an established database for identity verification– are to do things traditionally in the realm of governments not private companies. “Zuckerberg worries about this, it’s coming and it’s already started.”

Kirkpatrick can legitimately claim to have spotted Facebook’s protential early. He started the book in early 2008, when the service had around 50 million users. “It’s ten times larger now,” he points out.

However, Arrington repeatedly pointed out last night that he may be a little too close to this unique company, and Kirkpatrick didn’t always convince with his replies. When Arrington quoted a passage suggesting world peace might be brought thanks to the company connecting people the world over, his interviewee weaved, dodged and ended up largely repeating the claim using different words.

Still, Facebook is a remarkable company doing things like no other. With Kirkpatrick getting more access than anyone before, his book looks to be the best attempt yet to get inside that phenomenon.