by , 9:25 AM EST, November 29th, 2007

Adobe and Yahoo! announced on Thursday that they have teamed up to bring ads to PDF documents. The opt-in service for online commercial publishers is in a beta testing phase now, but promises to generate additional revenue by adding contextually appropriate ads to PDFs.

The advertisements Yahoo! plans on providing will be text-based, and will appear next to PDF content and not in-line. Adobe claims the ability to offer ads along side PDF content will also potentially allow publishers to offer more content for free.

Publishers that participate in the ad program must upload their PDFs to a special Adobe site where they will be encoded to include appropriate advertising. Once encoded, viewers will see ads that not only relate to the content they are reading, but are timely as well.

Participation in the Adobe PDF Powered by Yahoo! program is free. Additional information is available at the Yahoo! Web site and the Adobe Labs Web site.