Ads for PDF program from Adobe is a good opportunity for bloggers & other content publishers to monetize content via PDF files.
Ads for Adobe PDF inserts Yahoo! Ads (pay-per-click or CPC) into PDF files when viewed inside Adobe Acrobat Writer or Adobe Reader software. Each time the PDF content is viewed, targeted ads are dynamically matched by Yahoo to the content of the document. The publisher receives anonymized reports about which ads ran alongside which published content.
Ads for Adobe PDF enables publishers to monetize their PDF content through advertising. When a recipient opens a PDF document from a commercial publisher participating in this program, ads will be dynamically matched and displayed in a panel adjacent to the content. The publishers are eligible to be paid for valid clicks on the ads.