San Francisco--After announcing earlier in the week its acquisition of Ziff-Davis Inc., CNET Networks Inc. reported Thursday net revenue of $52.2 million for the second quarter, a 104% increase over the same period last year. CNET reported a net loss for the quarter of $20.7 million. It also reported pro forma net income of $2.5 million, excluding goodwill amortization, net gains on investment sales, and related taxes. CNET attributed the growth in revenue to an increase in traffic and a honed ability to monetize that traffic through advertising, lead-based revenues and licensing fees. CNET also reported it increased its number of advertisers to 900 in the second quarter, up from 364 in the second quarter of 1999.