Sadly there's one more niche for advertising to ply its charms. Yahoo and Adobe have signed a deal for Adobe to provide space in PDFs for Yahoo-pushed advertising. The joint communiqué — an ad-free PDF — can be found here. A publisher of information (U.S. only — for the time being?) registers with Adobe and uploads content; Adobe's algorithm then pairs that content with ads; the distributed registered PDF comes to you adorned with ads. As the articley on ZDNet says, perhaps it won't be so bad: who reads publishers' PDFs anyway?