He left Facebook in 2008. In June 2009, he started Quora with Charlie Cheever, another early Facebook employee.
D'Angelo competed in the Association for Computing Machinery collegiate world programming contest while attending the California Institute of Technology. In 2005, he was one of the top 24 finalists in the international Topcoder Collegiate Challenge. He took eighth place in the 2001 USA Computing Olympiad for high school students.
D'Angelo has been cited as one of the smartest figures in technology by Fortune magazine.