ImageCBS News said that the buy is an attempt for the media giant to grab a greater foothold on the Internet.

San Francisco-based CNet is the parent company of videogame consumer staple GameSpot.com, which has seen significant changes in its editorial department since the "Gerstmann-gate" debacle in late 2007.

CBS bought CNet shares for $11.50 a piece, a "massive premium" of 45 percent over CNet's most recent closing price, according to CBS. Other CNet sites include TV.com, mp3.com and News.com.

For CBS, one impetus behind the buy was to capture CNet's large online audience. The company intends to combine CNet's sites with CBS', increasing the media giant's visibility among a web-savvy crowd.

"There are very few opportunities to acquire a profitable, growing, well-managed Internet company like CNet Networks, Inc., which includes in its portfolio assets like CNET, ZDNet, GameSpot.com, TV.com, mp3.com, UrbanBaby, CHOW, Search.com, BNET, MySimon and TechRepublic," said CBS CEO Leslie Moonves.