Media is undergoing proliferation and fragmentation, as we are constantly told in the ad industry press. But the process may have bottomed-out with the latest (and oldest) ad medium - street walls.

A guerrilla marketing campaign for Sony's PlayStation Portable has taken to the streets in major cities such as San Francisco, Miami and New York, where building owners are paid to allow the use of wall space for graffiti-style ads. Sony claims it is targeting the "urban nomad".

Big-eyed kids, drawn in comic-book style, are portrayed with an unbranded, hand-size gadget. One licks his like a lollipop. Another is using the gizmo to play paddleball.

Sony is not alone in pursuing the holy grail of de-anesthetizing outdoor ads. Other big brands exploring the 'street art' approach include Nike, Nokia, Time magazine, even starchy old IBM.

According to Advertising Age's Bob Garfield, an increase in such edgy advertising campaigns, which attempt to create "buzz about buzz," are a sign that traditional advertising methods are failing.

Opines Garfield: "Marketers are desperate to find ways to reach people. Especially young men, who are far too busy playing Grand Theft Auto to notice, say, a 30-second TV commercial."

Genuine street artists, however, are outraged at the incursion of commercialism into their domain.

Patrick McNeil, of street-art collective Faile, accuses Sony of "trying to cash in on an art movement where they and the product they are selling don't belong". He dismisses Sony's painters as "an army of pimped-out artists."

Whereas on Madison Avenue ...

Data sourced from Washington Post Online; additional content by WARC staff