The 31-year-old announced his retirement from the microblogging platform in an emailed memo to staff Monday.
At its peak, Tumblr was an influential social media site where close-knit fandom communities could share writing and multimedia created and curated by bloggers and artists. The network’s presence began to decline following its $1 billion purchase by Yahoo in 2013. Now, Tumblr is under the control of Verizon, which acquired Yahoo in June and merged it with AOL to create a new subsidiary named Oath, which manages Tumblr.
In the memo, Karp said his departure “comes after months of reflection on my personal ambitions,” but did not detail any future endeavors.
Karp’s full memo to the Tumblr staff is below: