[8] In 1999, during his senior year at Harvard, Yagan and his classmates, Chris Coyne, Max Krohn, and Christian Rudder started TheSpark.com,[9][10] which would later be known as SparkNotes.

[17] In 2006, MetaMachine, Yagan, and founder Jed McCaleb agreed to pay $30 million to avoid potential copyright infringement lawsuits brought by the RIAA.

[18] In 2003, Yagan again teamed up with his Harvard classmates Chris Coyne, Max Krohn, and Christian Rudder to found online dating website OkCupid.

[21] Yagan was the CEO of Match Group for three years and left at the end of 2015 before joining the company's public board as vice chairman.

[26] In 2016, Yagan became the CEO of ShopRunner, an e-commerce network that provides two-day shipping across multiple merchants that was founded by Michael Rubin.

[31] Yagan has participated on the board for several companies including Grindr,[32] Match Group,[33] Rush University Medical Center,[34] Start Early,[35] Shiftgig,[33] SpotHero,[33] Tinder,[33] and Techstars.