If you publish PDF documents, try the Ads for Adobe PDF program to display advertisements in PDF documents and earn money. Though the program was launched some time back, Adobe has optimized the Adobe PDF ads for higher earnings.
Adobe PDF ads
Choose how ads are matched to your PDF. If your pdf has a main topic, choose Match ads for the entire PDF to dynamically match one set of ads to the PDF and display this same set of ads on every page. If there are multiple related topics, then choose Match ads for each page to dynamically match and display a different set of ads on each page. That will make ads more targeted leading to a better CTR.
What if the user is offline and no targeted ads can be shown? Now you can restrict viewing of the PDF when ads cannot be displayed and a coversheet is displayed on the PDF which asks the user to download the latest version of the free Adobe Reader and/or connect to the network, after which only the coversheet is removed and you can view the PDF with ads. So users are forced to load ads…
Display ads within the PDF content – The ads are no longer stuck in the sidebar as a tall skyscraper. You can place ads where you want them in the PDF and customise ad sizes, ad color palettes, borders, background and text colors. Blend it in and improve visibility.
Adobe has partnered with Yahoo! to provide contextual ads to match PDF content and the program pays per click! With all these new features, Adobe PDF Ads is definitely a advertising program to look out for and monetize your PDF documents.