Passage: Chen was an employee at PayPal, where he first met Chad Hurley and Jawed Karim. Chen was also an early employee at Facebook, although he left after several months to start YouTube.In 2005, Chad Hurley, Jawed Karim and Chen founded YouTube, with Chen having the position of chief technology officer. In June 2006, Chen was named by Business 2.0 as one of "The 50 people who matter now" in business.On October 16, 2006, Chen and Hurley sold YouTube to Google, Inc. for $1.65 billion. Chen received 625,366 shares of Google and an additional 68,721 in a trust as part of the sale. As of 2018, the Google shares are valued at $729 million.He and Hurley started AVOS Systems which acquired Delicious from Yahoo! Inc.

Question: Who previously worked at Facebook?
Chen