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We've never gotten a straight story on why Facebook CEO Mark Zuckerberg took off for a trip around the world. Work or pleasure? Our latest tipster says that Zuck's travels are really about about avoiding the unpleasantries of business — specifically, easing out some of Facebook's old guard, like CTO Adam D'Angelo. Here's what he passes on:

More recently, a very high up manager in Facebook contacted me saying that Mark is a senstive soul about some matters, and did not want to be around when his friends were being "let go"/"leaving to pursue other passions."

Put another way, Zuckerberg is giving new COO Sheryl Sandberg room to run the place unsentimentally. It's a reminder that Zuckerberg is both brilliant and young, having just turned 24 on Wednesday. He's immature enough to be uncomfortable firing people, and yet self-aware enough to realize that's a problem. (Photoillustration by Jackson West