Shazam has 300 million users

"The number of Shazam users and their level of engagement continue to grow rapidly. We now have over 300 million Shazamers globally with an increasing proportion of whom use our app on their iPad or Android tablet devices to interact with television. This new version of Shazam optimizes discovery, engagement, transactions and exploration in a tablet environment,” said Andrew Fisher, Shazam CEO. “It’s the most efficient way to experience more of the media around you whether you are in your home or in any other environment throughout the world."

Source:  Press release from Shazam, 25th February 2013

Earlier - 250m announced in September 2012

Earlier - 75m announced in May 2012