Pintrest, the digital vision board for social photo sharing, is hot. ComScore found that Pinterest just hit 11.7 million unique monthly U.S. visitors, who spend an average of 98 minutes a month on the site, compared to 2.5 hours on Tumblr, and 7 hours on Facebook.
Pinterest has been around since 2008, but it took a while to build critical mass. One expert, Dr. Christopher Long, a professor at Ouachita Baptist University, points out that Pinterest, like Facebook, relies on people generating content that interests other users, so once a critical mass of people comment and re-pin, it reinforces others to generate content. The more content is generated, the more it makes sense for users to frequent the site.