Sony Corp. scouted out an unusual place to advertise its PlayStation Portable before the holidays: the side of an abandoned building in a gritty North Philadelphia neighborhood.

The black-on-white graffiti shows wide-eyed cartoon characters riding the PlayStation like a skateboard, licking it like a lollipop or cranking it like a Jack-in-the-Box.

But there's no mention of the Sony or PlayStation brands — nor any hint the wordless display is an ad.

The stealth marketing campaign has popped up in San Francisco, New York and other large U.S. cities.

"It's all about hip-hop, urban and all that. They're just trying to get into the teenagers' minds," said Eddie Torres, 29, who works at a nearby furniture shop. "I think it's sharp."

Anti-blight advocates think otherwise.

"They're breaking the law," said Mary Tracy, who runs the Society Created to Reduce Urban Blight, a watchdog group that fights illegal or ill-advised billboards in Philadelphia.

Tracy said Sony ignored the zoning process that regulates outdoor commercial advertising in the city.

Philadelphia Managing Director Pedro Ramos on Wednesday faxed a cease-and-desist letter to Sony Computer Entertainment's U.S. division in San Mateo, Calif. He could seek modest fines allowed by city code or sue to recover any profit the ads produced.

"My fines aren't going to scare Sony," Ramos said. "What will worry them is what the parents and their users will think. This really flies in the face of everything we've been trying to do with our anti-blight initiative."

The Sony division did not immediately respond to the letter or to a telephone message left by The Associated Press. However, Sony spokeswoman Molly Smith told an Internet news site earlier this month that Sony was hiring artists in seven cities — Atlanta, Los Angeles, Miami and Chicago were the others — to spray paint the pre-drawn designs.

"With PSP being a portable product, our target is what we consider to be urban nomads," Smith told Wired News.

In San Francisco, the ads were defaced soon after they appeared as word spread that Sony was behind them. "Get out of my city!!!" and "Fony" were written on one.

"I thought it was sneaky. Not cool," said Zan Sterling, who works at a bar near one of the ads, which has since been painted over. "I hope that they paid for the cleanup and removal."

Critics and supporters agree the campaign is designed to crack through the clutter of marketing that pervades daily life. Others have criticized its visual appeal.

"They hired artists to just copy this same figure over and over, which isn't too creative," said 29-year-old Jake Dobkin, a New Yorker who writes for the blog Gothamist.com.

That matters little to North Philadelphia resident Leslie Griggs, 39, who said the Sony ad is an improvement over the handbills and scrawls it replaced.

"I don't think that's graffiti," Griggs said as she paused beside the PlayStation ad. "That's art."