Opera Software, maker of the Opera and Opera Mini browsers, yesterday announced an acquisition of Mobile Theory and 4th Screen Advertising to expand its offering to advertisers and mobile publishers.

Opera offers advertising solutions for mass-market feature phone and smartphone platforms, including iOS, Android, Blackberry, Java and Symbian.

The company says the acquisition will enable Opera to better monetize the traffic that flows through Opera Mini and Opera Mobile browsers. Opera boasts over 160 million monthly active users that generate more than 100 billion page views, and consume more than 16 Petabytes of mobile data services a month, as of December 2011.

Mobile Theory is a mobile advertising network focused on the U.S. mobile advertising market, based in San Francisco, with offices in New York City, Chicago, Los Angeles and Seattle.

4th Screen Advertising is a leading premium mobile advertising network focused on serving the European mobile advertising markets, based in London.