How to denouce a scam exchange? I was scammed by an exchange called BitNake. It is referenced in the Bitcoin Wiki as a fast and secure exchange seeded in Germany. I could not find any negative comments on the web and decided to try it. I paid the minimum amount but never got any Bitcoin deposited in my wallet. Repeated e-mails to the support address went unanswered.

As it turns out, the BitNake website seems to have been created just last month and is actually installed in California. I guess I am one of the first to fall for this.

The question then is: how do I tell the world this website is a scam? So that others do not fall for it too.

Update I: here is the scam report at CoinTalk.

Update II: BitNake had been previously reported as a scam. However the search engine I use, DuckDuckGo, seems to be blind to BitcoinTalk. Another interesting aspect in this story is PayPal actively protecting the scammer.
Spreading the word about your experiences (and supporting it by the hard facts of website domain registration etc.) is the best way. You might be able to edit the wiki entry to add a warning. In addition, the scam accusation section on bitcointalk.org might be a good place to make your warning visible to many potential victims.