Very interesting story developing in the world of anonymous internet postings. From http://network.nationalpost.com/np/blogs/fpposted/archive/2009/11/19/fp-tech-desk-kurt-greenbaum-vs-the-vulgar-commenter.aspx :
On Friday, Mr. Greenbaum (who is the newspaper's "director of social media") wrote a post on the Post-Dispatch's site entitled "What's the craziest thing you've ever eaten? And did you like it?" (comments are now closed).
Sometime later, a reader posted a single word comment to the story, which Mr. Greenbaum described as "a vulgar expression for a part of a woman’s anatomy."
Although the post was quickly deleted by someone at the newspaper, the same user posted the same comment shortly thereafter.
It was then that Mr. Greenbaum noticed the user's IP address showed that the person was posting the comment from a nearby school.
In a controversial move, Mr. Greenbaum decided to call the school. The principal asked Mr. Greenbaum to forward him the email which contained the IP address, which he did.
Six hours later, Mr. Greenbaum received a call from the principal, who told him that with the help of the school's IT director, they had figured out who posted the comment. When they discovered it was one of the school's teachers, the principal confronted the teacher, who resigned on the spot.
It seems to me that this would be a violation of the site's privacy policy, but I don't know enough about that to say for sure.
This might be a good time to review letsrun.com's privacy policy:
http://www.letsrun.com/privacypolicy.php