While he has left Tumblr as an official executive, Arment (pictured left) said on his blog that he will still be involved with the company as a consultant. Arment served as Tumblr’s lead developer for four years.
“Tumblr’s technical management needs have evolved to require types of experience that I don’t have,” he wrote in a blog post earlier today.
Arment’s departure comes at a time as Tumblr has taken a definitive lead over competing lite-blogging service Posterous in terms of usage and traffic. He said he is not seeking outside investment for Instapaper, a browser-based application that lets users save web pages to “read later.” He also said he will work on other personal projects as he finds time for them.
Tumblr lets users create their own blogs from an existing library of templates and hosts those blogs for free. The New York-based company raised more than $10 million by April, with three rounds of funding led by Union Square Ventures and Spark Capital.