Social Website Regulation?

BBC News has details on an investigation into social networking sites by Which? which concludes that social networking sites such as MySpace and BeBo need to do more to protect their members. Protect their members from what...themselves?

I agree that identifying their users would stop many problems. Often times, all these websites have to identify their users are email addresses. But, as I see it, any sort of verification may require a credit card, which would preclude anyone under the age of 18 from joining; A major loss for the website, especially ones like MySpace who's big money maker IS that demographic.

Is this a tool that should be limited or regulated like alcohol, guns or lighters? Those tools are only dangerous depending on how you use them and who is using them. So what is the argument for not regulating these types of sites?