Tumblr is a shadow figure in the social-media world. Quantcast calculates that Tumblr receives 44 million visitors each month, but the three-year-old social blogging platform still ranks behind Facebook(Nasdaq:FB), Twitter, and Pinterest in popularity with users—and with advertisers.
Companies need to be able to measure the results of advertising campaigns for a platform to provide real value. With Tumblr’s announcement Thursday it has named Austin-based Union Metrics its official analytics tool, Tumblr is now a legitimate competitor for a business’ advertising dollars.
http://upstart.bizjournals.com/companies/media/2012/10/08/tumblr-analytics-makes-site-legitimate.html