Tumblr's longtime CEO David Karp is leaving the company after 10 years. Karp sent out this tweet of a goodbye letter he sent to his former team. Karp's letter reads He is expected to leave by the end of the year and will be replaced <br />by COO, Jeff D’Onofrio. Karp sold Tumblr to Yahoo in 2013 for $1.1 billion, before it flopped and declined in popularity. Tumblr is now owned by Verizon-owned media conglomerate Oath.
