Tumblr CEO and founder David Karp, who created the blogging site more than 10 years ago at the age of 20, is resigning from the company. The news, first reported by The New York Times, was confirmed to The Verge in a statement from Verizon-owned media conglomerate Oath, to which Tumblr belongs, following a dizzying string of mergers and acquisitions over the last four years.

“David Karp will depart Oath by the end of the year,” the statement reads. “David founded Tumblr 10 years ago as a space for the world’s creators, and we thank him for his commitment and passion driving the growth of the platform to almost 380 million blogs and over 155 billion posts.”

Since 2013, Tumblr has been a property of Yahoo following a $1.1 billion acquisition that put the social network and Karp, still its CEO, under the guidance of then-Yahoo chief executive Marissa Mayer. Four years later, Yahoo was sold to Verizon in a deal that was finalized earlier this year with Mayer’s departure back in June, making Karp a Verizon employee as part of a combination of AOL and Yahoo’s assets that came to be called Oath.

The many corporate reshuffles may be why Karp has finally stepped down, although it’s unclear exactly why he’s leaving the company or what he plans to do now. According to the statement, Tumblr Chief Operating Officer Jeff D’Onofrio is taking over for Karp. An Oath spokesperson later confirmed that D’Onofrio will lead Tumblr going forward as its permanent CEO.

Karp, in a note sent to his colleagues at Tumblr, says the “decision comes after months of reflection on my personal ambitions, and at no cost to my hopefulness for Tumblr’s future or the impact I know it can have.” He goes on to say, “The internet is at a crossroads of which this team can play a fundamental role in shaping.”

Letter I just sent to my team ♥️ https://t.co/3Vsv3ROuhf — David Karp (@davidkarp) November 27, 2017

Regardless of his underlying motives, Karp’s resignation marks the end of an era for Tumblr, which became a blogging juggernaut and home to the internet’s more idiosyncratic personalities during the mainstream and meticulously corporate rise of Facebook. Over the years and under Karp’s leadership, Tumblr offered a platform to writers, artists, other creators with a unique penchant for fandom and a peculiar and unique aesthetic, giving those voices a place to express themselves, find a following — and occasionally go viral in ways reminiscent of the earliest days of web blogging.

Update at 4:08PM ET, 11/27: Clarified that Tumblr COO David D’Onofrio will be Tumblr’s new, permanent CEO now that Karp is leaving.