NEW YORK — CBS Corp. is acquiring a big online reach with its acquisition of CNet Networks Inc. but also a company that's faced heavy criticism from investors. Those concerns as well as the hefty $1.8 billion price tag helped send CBS' shares down after the deal was announced Thursday.

CNet was an early player in the dot-com boom and survived the subsequent crash with a steady focus on technology news, reviews and entertainment. But its stock, which once traded as high as $79 during the bubble, has slumped over the last two years, leading to an investor rebellion that was gathering steam just as the CBS deal was announced.

CBS's chief executive, Leslie Moonves, said acquiring CNet would lift CBS into the top 10 online audience companies in the United States, giving CBS new ways to distribute its news, entertainment and other programming.