When Tumblr president John Maloney joined the staff four years ago, the blogging community had yet to achieve runaway success.

Now it has. And Tumblr no longer needs him.

In a resignation post titled “Tempus Fugit,”—Latin for “Time flies,”—Maloney announced today that he’ll be stepping down as president, effective immediately.

“I told the team and board this week that it’s time for me to transition away from running day-to-day operations,” he wrote. “It’s the right time for me and a good time for Tumblr.”

In a related post, CEO David Karp wrote that Maloney joined Tumblr during a difficult time for the site. Karp said he was having trouble running the company by himself, and asked his old friend Maloney for advice.

“I asked if he might help me get things in order at Tumblr,” wrote Karp. “He said he’d set up his desk the next day. I don’t know exactly what happened after that because—like he does—John magically put everything in order.”

In the four years since, Tumblr has grown exponentially. The site hit 20 billion posts in March. The word “Tumblr” will soon surpass the word “blog” in Google search popularity. Karp can no longer call Tumblr “the underdog” of social media.

Maloney said users shouldn’t notice a change now that he’s gone—he said the Tumblr team “plans to ship some awesome new stuff next week.” But based on hundreds of notes and reblogs on Karp’s repost, it’s clear that he’ll be missed around Tumblr, and especially at Tumblr HQ.

“John is one of my favorite people,” wrote Topher Chris, Tumblr’s community manager. “I hope I’ll always be able to text him random stuff without it ever getting weird. Thanks for everything, boss.”

Photo via @JohnMaloney