Reid Hoffman cofounded professional networking site LinkedIn in 2003 and is a partner at venture capital firm Greylock Partners.In 2016, Hoffman sold LinkedIn to Microsoft for $26.2 billion in cash and joined Microsoft's board.He is an investor in Airbnb, which went public in December 2020, and autonomous driving pioneer Aurora, which acquired Uber's self-driving unit.Hoffman is part of the so-called "PayPal Mafia," and was one of the first employees at the payment company that was later sold to eBay.Before PayPal, Hoffman created the (failed) dating site SocialNet, which some regard as the first online social network.He has put $1.5 billion into impact investments through charitable entities like donor-advised funds; Forbes excludes this sum from his fortune.