REUTERS/Brian Snyder
A couple years ago, it was to wear a tie every day. The next, to learn Mandarin. Last year, he swore off all meat that wasn't from an animal he killed himself.
He just told Fortune magazine what his personal challenge is this year: to meet a new person every day.
"I’m meeting one new person outside of Facebook every day. Who doesn’t work at Facebook. It’s going well—I’ve done a bunch of things in the community and just tried to get broader exposure."