Good article at Wired covering the implausibility of do-not-spam lists.
The point that gets missed most often by supporters of do-not-spam lists is that we should all, automatically be on a do-not-spam list. Only if I give you permission should you be able to contact me by e-mail, commercially. “Everyone on the list” means that there is no need for a list, only for permission. Everything else is pretty much unworkable.