After her jackass ex-boyfriend created fake profiles on Yahoo! to persuade other men to call her repeatedly for sexual favours, Cecilia Barnes found little help from Yahoo! in having them removed.
Barnes broke up with her boyfriend in 2004, and in a fit of total jackassery, he not only created fake profiles of her but used them in chat rooms to tell creepy dudes to check them out. These profiles contained "some kind of open sexual solicitation," and said creepy dudes soon started "peppering [Barnes']office with e-mails, phone calls, and personal visits, all in the expectation of sex." As Ars notes, it's basically the modern equivalent of scrawling a phone number on a bathroom wall, only with a lot more initiative.
Because the profiles were fake, Barnes took the appropriate measures to have them officially removed from Yahoo!, by sending in her proper ID and explaining the situation. Yahoo! agreed, and promised to take the profiles down, and then...didn't. Even after a Yahoo! rep personally assured her the profiles would be removed, no action was taken. So Barnes sued Yahoo!.
Publishers like Yahoo! (and Craigslist, and Facebook) have immunity from being prosecuted for the actions of its users, so they were ruled not guilty. But due to the media attention brought by the lawsuit, Yahoo! finally got off their arse and remedied the situation like they should have months earlier. The judge was particularly sympathetic to Barnes, advising her that she could refile the suit as a sort of "breach of contract" suit, alleging that when Yahoo! agreed to remove the offending material, they became contractually obligated to do so.
We personally agree with the judge's decision; had he held Yahoo! responsible, it's an awfully slippery slope. But sites like Yahoo! do have an obligation to their customers to take complaints like these more seriously. [Ars Technica, Court Decision (PDF)]