The Swedish Media Council published a report yesterday where they look at the social networking sites used by kids today (Facebook and Youtube among others).
The study is done from a Swedish perspective, which reflects the sites selected for the study, as well as the basis for what criteria should used for the study to some extent (they base part of the criteria on the Swedish law Law on responsibility for electronic billboards (1998:112), also known as the BBS-law).
They mainly look at how safe the site is from a user (kids) perspective. Safety here focuses on handling of user information, how user reports/issues are handled, conditions for membership and how easy it is to get information on, and in contact with the people running the site.
Unfortunately, the report does not go into all the details on the data they should have gathered in their research. Still an interesting read, and it should provide a good guide for parents looking out for their kids online.
The report is available as a download here. In Swedish only as far as I can tell.