Tumblr was an accidental social network, said founder and CEO David Karp, speaking at the DLD conference in Munich today.

In its early days, the service didn’t have the “steep social network growth” you might expect, because it was about a core community of creators, Karp said. The company originally set out to build novel tools that offered an escape from the restrictive templates of Facebook and Twitter.

When the site really took off was when the curators — people who primarily respond to other Tumblr users’ content by “reblogging” it on their own pages — came on board.

Today, creators are probably 10 percent of Tumblr, and curators are 90 percent, Karp estimated.

via Tumblr’s Inflection Point Came When Curators Joined Creators – Liz Gannes – Social – AllThingsD.