Yahoo (YHOO) didn’t disclose how much it is paying in the acquisition, though TechCrunch cited an anonymous source who pegged the price between $200 million and $300 million.

Yahoo is trying to quickly lift its mobile ad business, which lags far behind rivals like Google, Facebook and Twitter. It’s an area that CEO Marissa Mayer has identified as critical to revitalizing the Web portal, and the Flurry deal marks one of her biggest acquisitions during her two-year tenure.

The San Francisco-based company’s analytics are used by 170,000 developers and it is currently running on more than 1.4 million mobile devices, according to Yahoo’s announcement of the deal.

Yahoo said the combination “will accelerate revenue growth for thousands of developers and publishers across the mobile ecosystem.” Yahoo said last week that it gets nearly half of its audience from mobile visits, but the company’s mobile ad sales are so insignificant that it does not break them out separately in earnings reports. (The company has merely graduated to referring to those revenues as “meaningful” in more recent earnings calls after previously calling them “not material”.)

The global market for mobile ads is expected to top $32.7 billion this year, according to research company eMarketer, a jump of 85% from last year. Google (GOOG) and Facebook (FB) made up more than two-thirds of that worldwide market combined last year.