Porn will power the mobile e-conomy, according to PK Entertainment, a Baltimore-based peddler of erotic scribblings.

PK - run by a husband and wife team - provides naughty stories for PDA users to download and read on their palmtops.

PK's tales are free - the company's Web site, which the couple claims is "very profitable", makes its money from advertising. But whether revenue streams come from users or advertisers, PK's Kathryn Hudson reckons that demand for adult material on discreet, portable devices will expand significantly.

Ancillary services PK is planning include a scheme to send users on the move the locations of nearby strip joints, video stores and sex shops straight to their mobile devices.

It's often said that the smut business established VHS as the de facto home video standard over the technically superior Betamax, so never underestimate the pulling power of porn. Adult material could prove the killer app the likes of WAP have been waiting for. ®