Tumblr isn't just for teens anymore.
In fact, Tumblr recently announced in a blog post that an audience of 168 million people has pushed the social network into the ninth spot of Quantcast's top ten U.S. Websites.
The social blogging site, which was launched in 2007, is most popular amongst the 18-24-year-old demographic. However, many top brands have already taken advantage of this network's popularity and solidified a presence on the site, including apparel retailers Macy's and Urban Outfitters and content publishers Time Magazine and The Onion.