Tumblr is now the fasted growing social media platform, it's a little bit blogging and a little bit social.
I thought this article was a good introduction to Tumblr. While it is from a job recruiters point of view the article does have value for any business doing social media marketing and community management. 

#tumblr   #blogging   #socialmedia  
Tumblr for Recruiting: What Employers Need To Know

One of the primary benefits of Tumblr is that you can post pretty much anything on there, and users do – from blog posts to external links to .gifs to videos and more. That open structure and relative lack of limitations is a big driver behind Tumblr’s user growth – and over the last year, that growth has been co-opted by a steady stream of celebrities and public figures. It’s even created a few celebrities of its own, with top Tumblr users attracting huge followings and fan bases numbering in the millions.
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