Some sites go much further: Disney's Club Penguin offers a choice of viewing either filtered chat that avoids blacklisted words or chats that contain only words that the company has pre-approved.
They can also alienate some of a site's target audience - especially teen users who expect more freedom of expression.'There are companies out there that are doing a very good job, working within the confines of what they have available,' said Brooke Donahue, a supervisory special agent with an FBI team devoted to Internet predators and child pornography.
'There are companies out there that are more concerned about profitability.'Also in June, a teen-oriented virtual world called Habbo Hotel, which boasts hundreds of millions of registered users, temporarily blocked all chatting after UK television reported that two sex predators had found victims on the site and that a journalist posing as an 11-year-old girl was bombarded with explicit remarks and requests that she disrobe on webcam.
Software recognised that the same person had been making similar requests of others and flagged the account for Metaverse moderators.
They called the media company, which then alerted authorities.
Such efforts generally start with automated screening for inappropriate language and exchanges of personal information, and extend to using the records of convicted pedophiles' online chats to teach the software what to seek out.