First came the soaring ascent of online social networking sites and now comes old fashioned soul searching about a sprawling universe where staid advertisements can scrape up against profiles of giddy young professionals and pages devoted to self-proclaimed angry "straight, white men."

While sites like Facebook, MySpace, Bebo and Habbo Hotel have a powerful allure, the companies that run them are finding themselves on the front lines of criticism about fast-evolving standards. Some of the criticism in Britain involves advertising for junk food that is migrating to the sites from children's television programming, where such ads are now banned, and corporate concern about employees distracted by time-sapping virtual networking.

For traditional advertisers rushing headlong into this new territory to reach tantalizing, young users, the ultimate nightmare is the surprise of sharing virtual real estate with risqu? material or racist rants.

"Ultimately there are going to be mistakes and unfortunate incidents," said Debra Aho Williamson, a senior analyst with the research firm, eMarketer, and the author of a report predicting that global advertising spending on social networks would grow to $3.6 billion by 2011 from $445 million this year.

Get the full story at the International Herald Tribune