Adobe will soon be bringing pay-per-click ads to a PDF near you, as the result of their latest deal with Yahoo.

Apparently, Adobe and Yahoo have decided that PDF documents are an untapped market for content-based ads. The partnership provides for Yahoo ads to appear in a side-panel of Adobe's PDF software, dynamically matched to the content of the PDF document. Adobe expects the new technology will provide a method for content producers to continue offering their content to users for free, subsidized by pay-per-click advertising.

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