CBS (NYSE:CBS) said this week it completed its $1.8 billion acquisition of CNET Networks and merged the properties into its own interactive division. The new unit comprises all the online properties of the New York-based Eye network and CNET, located in San Francisco.

The combined assets now make CBS“s the eighth largest Web outfit, with 54 million unique visitors per month, according to May comScore data. It also puts CBS Interactive in the top five of ad-supported premium content sites, and it the second place online entertainment and sports destination among 18-to-24-year-old males.

CBS Interactive includes five verticals--technology, in the form of CNET.com; entertainment, a la CBS TV shows; sports, professional and NCAA; news and business.

Quincy Smith, head of CBS Interactive since November, 2006, was named CEO of the new division, and CNET chief Neil Ashe becomes president.