VeriSign continued its efforts to break into the mobile media business Monday with the acquisition of m-Qube, a company that assists in the development, delivery, and billing for mobile content. The purchase is VeriSign's third in the sector, following 3united and Kontiki.

While it is better known for Internet security and management of the .com and .net domains, VeriSign also runs a mobile content business. However, it only contributes about a fifth of the company's overall revenue.

m-Qube already runs premium messaging and content services for several major brands, including Sony Pictures, CBS, Major League Baseball, Warner Music, and Reuters. These services have the capability of reaching 200 million subscribers in North America.

Through the acquisition, VeriSign said the added expertise would better its content delivery services for carriers, Internet portals, media companies and consumer brands.

"VeriSign is combining its world-class expertise, applications and infrastructure to make content convergence over any network and any device a reality. m-Qube will increase our leadership and expand our services in this emerging category," VeriSign's executive vice president of communications services Vernon Irvin said.

The company paid $250 million for m-Qube. The merger is expected to close in the second quarter of this year.