"In almost all cases it is not possible to bring a civil action against" a website that hosts your nude images posted without your consent.
This past July, Forbes blogger Kashmir Hill posted a three-part series about "online defamation and involuntary nudity." The first entry focused on an offender: Hunter Moore, owner of IsAnyoneUp.com (Link is NSFW.) The second entry focused on a victim: Paul Syiek, whose company was defamed by a disgruntled ex-employee on the consumer website Rip-off Report. The third profiled a Senior Copyright attorney at Microsoft, Colette Vogele, who co-founded a side project this year to help victims: WithoutMyConsent.org. [more inside]
The Supreme Court of Canada has agreed to hear a case deciding whether or not posting a link to allegedly defamatory material constitutes defamation itself. The complainant lost his case in 2008 at the British Columbia Court of Appeal. The complainant has launched various lawsuits in the past against numerous websites and blogs; all have been unsuccessful thus far. [Previously, RE: a similar case in Australia]
Kentucky Lawmaker Wants to Ban Anonymous Internet Posting. This bill is pretty much a nonstarter, but should online defamation be criminalized? [pdf]
New Jersey Assemblyman Peter Biondi didn't like that he and his friends are getting flamed on the news portal NJ.com by people named, inter alia, "frenchtoast2." So he introduced a bill, and that bill would require "operators of interactive computer services" to make members' real names available upon demand, and allow content providers to be sued for contributory defamation. And he saw that this was good. And that was the first day.
The High Court of Australia has decided that you can defame someone in Australia by posting an article on a website hosted outside Australia, if that article is read by people inside Australia. I suppose this means that anyone posting on the internet is subject to Australian defamation law. (Unless you decide to block requests from Australian browsers.)