CNet Networks ( CNET) shares sank late Monday after the interactive media outfit swung to a third-quarter loss. The San Francisco-based company lost $3.4 million, or 2 cents a share, in the quarter ended Sept. 30, reversing the year-ago profit of $1.1 million, or a penny a share. Excluding an $8.9 million noncash asset impairment charge and $1.9 million loss on investments related to the full writedown of an investment in two private companies, the latest-quarter profit was $7.5 million, or a nickel a share. Revenue rose 22% from a year ago to $86.3 million. Analysts surveyed by Thomson First Call had forecast a third-quarter profit of 4 cents a share on sales of $86.8 million. For the fourth quarter, CNet guided Wall Street to expect a profit of 13 to 16 cents a share on sales of $102 million to $109.5 million. Analysts were looking for a 14-cent profit on revenue of $109 million. Late Monday, CNet shares slipped 98 cents to $12.54.