Mark Zuckerberg doesn’t usually observe sentimental anniversaries. This year he’s confronted by three of them. On Feb. 4, Facebook, the company he co-founded in a Harvard University dorm, turns 10 years old. The prodigy himself turns 30 in May. It’s also been a decade since his first date with Priscilla Chan, now his wife, whom he first met in line for the bathroom at a Harvard fraternity party.