San Jose-based Adobe Systems and Sunnyvale-based Yahoo said last night that the two have launched a new service which adds advertising to Adobe's Portable Document Format (PDF) files. The two said that the opt-in service will allow publishers to include contextual ads next to PDF files. According to the companies, the advertisers will be powered by Yahoo, which will provide access to its network of advertisers. The new program, which is in beta, requires content creators to upload their Adobe PDF files so that ads can be inserted into the content. The firms said that IDG's InfoWorld, Wired, Pearson's Education, Meredith Corporation, Reed Elsevier, and others have joined the beta program.