"Mr. Coatney describes Tumblr as “a space in between Twitter and Facebook.” The site allows users to upload images, videos, audio clips and quotes to their pages, in addition to bursts of text."

Mr. Coatney describes Tumblr as “a space in between Twitter and Facebook.” The site allows users to upload images, videos, audio clips and quotes to their pages, in addition to bursts of text.

One of the big differences between Tumblr and Twitter is that Tumblr does not display how many followers a user has, said David Karp, Tumblr’s 24-year-old founder and chief executive.

“Who is following you isn’t that important,” he said. “It’s not about getting to the 10,000-follower count. It’s less about broadcasting to an audience and more about communicating with a community.”