Tumblr has 17.5 billion page views a month

"Karp likes to talk about Tumblr less as a business than as a “platform for creativity.” And indeed, it has been used to make more than 60 million blogs — among them a visual scrapbook kept by Michael Stipe; silly meme-blogs like Hey Girl, It’s Paul Ryan; and the clever graphic analysis that became the recent book “I Love Charts” — drawing a combined 17.5 billion page views a month."

Source:  New York Times, 12th July 2012