Tumblr is a re-envisioning of tumblelogging, a subset of blogging that uses quick, mixed-media posts. The service hopes to do for the tumblelog what services like LiveJournal and Blogger did for the blog. The difference is that its extreme simplicity will make luring users a far easier task than acquiring users for traditional weblogging. Anytime a user sees something interesting online, they can click a quick Share on Tumblr bookmarklet that then tumbles the snippet directly. The result is varied string of media ranging links and text to pictures and videos that takes very little time and effort to maintain.
There is little to no learning curve involved in using tumblr. Features are intuitive and quick to establish. Users simply sign up and begin posting in a minute.
Tumblr is backed by Union Square Ventures, Spark Capital and Sequoia Capital.