CBS Corp announced today it plans to buy San Francisco web media company CNET Networks for about $1.8 billion to boost the television broadcaster’s reach across the Internet, Reuters and others are reporting. The deal could also put to rest a brewing fight between CNET and an activist investor group led by hedge fund Jana Partners, which wants to shake up the Web company. At right are workers at CNET’s SF office. (Photo credit: Paul Sakuma, AP)

The high premium CBS is paying reflected both the urgent desire of media companies to build online audiences for their programming as their viewers and advertisers go there but also the relative scarcity of potential acquisition targets that can offer such reach, AP says. Acquiring online audiences was a main goal behind Microsoft’s recently failed bid to acquire Yahoo.