90% Of Users Join Tumblr From Blogs, 85% Of Those Users Are Still Blogging A Week Later

Tumblr founder David Karp and Instagram founder Kevin Systrom took the stage at TechCrunch Disrupt to talk about the hockey stick growth of their respective companies. Tumblr in particular is showing insane growth numbers; On May 16th, 2011 Tumblr did 250 million pageviews, more pageviews than it had in all of July 2009. That record was then surpassed six days later, at 275 million pageviews on Sunday May 22th. There were also 34.3 million posts on that Sunday, also a Tumblr record.

Perhaps the service is demonstrating sustained success because of its organic user acquisition methods; 90% of Tumblr’s new registrations come through Tumblr blogs themselves.

Says Karp on the new users, “90% come from the Join Tumblr button up in the corner of blogs, the Follow button on blogs, typing in Tumblr after you’ve visited a blog on Tumblr so you’re trying to investigate what this thing is that they’re using, or clicking the Powered by Tumblr link at the bottom of the screen.” This means that the other 10% are either typing in Tumblr.com directly or Googling. Once registered 85% of users are still posting a week after sign up.

There are currently almost 20 million blogs on Tumblr, and that number seems to be rapidly rising. “Frankly, [there’s] pretty little incentive to sign up,” says Karp. “It’s not like you have to register to comment on those blogs or to interact with them. But people see these things that people are doing with Tumblr and it inspires them to want to try that for themselves.”