You can get de-registered by posting a topic like this.
Anyway I recalled reading that it's against some data protection or privacy law if the company or organisation refuse to remove unsolicited private information or user profile when explicitly requested by the person concerned. Not too sure if this applies to internet forum though.
btw, if anyone want to get yourself de-registered, don't have post so lengthy topic and postings. or go and poke Admin, Mods or anyone in CS.
just start a thread selling shoes, watches, handphone in CS will do, you will get de-registered within 20mins, sometime even shorter, if any mods happen to be online.