Because Pfizer isn't an internet service provider, it isn't allowed under the Can-Spam Act legislation to sue spammers, so it hooked up with Microsoft to do battle with 17 floggers of fake Viagra, according to ClickZ. Pfizer has standing already to sue imitators on trademark grounds and several other commercial measures, but has not been able to enjoy some of the legal benefits and powers granted ISPs in spam cases. The odd provision of the Can-Spam Act makes ISPs gate keepers of sorts to courts in addressing spam-related cases. The measure was originally intended to limit potentially innumerable federal civil actions to just those where the ISPs themselves had grievances, presumably because of bandwidth issues and customer user experiences.