Adobe has teamed up with struggling web 'giant' Yahoo! to enable PDF publishers to include relevant contextual ads next to PDF content.

The key word here is 'next.' The ads won't actually be inside the PDF doc itself. Instead they'll be shown in a panel on the side of full-fat Acrobat or Acrobat Reader.

Adobe is inevitably putting a positive spin on this potentially annoying service by saying that it "has the potential to offer readers access to more free content, enhanced with ads that match their interests."

The actual winners are the advertisers - who get yet another way to flog their various wares to us - and Yahoo/Adobe and content providers who all take a cash slice.

Ad-funded free content?

"We are creating opportunities for publishers to build new businesses around unique content that previously was just given away or not available to a mass online audience," said Rob Tarkoff, head of Corporate Development at Adobe.

"As advertisers look to touch new audiences, readers can look forward to some exciting Adobe PDF content coming their way." Quite what kind of content could be provided, but it would make sense if content that is usually paid-for in other ways (like in magazines) was able to be given away in an ad-funded scenario.

The application, Ads for Adobe PDF Powered by Yahoo, is initially available as a beta from Adobe Labs, home to another of our favourite web apps, word processor Buzzword. Advertisers will be able to take part in the beta by registering and uploading their PDFs to be 'ad-enabled.'

Every time the PDF is viewed, contextual ads are matched to the content of the document.