I'm kind of in an odd situation, I work for an antispam company and am working on a charity project to prevent counterfeit drugs.

Those Viagra ads? One of my collegues on the charity work mentioned a stat, not sure where the source was, but roughly 80% of internet marketed Viagra is counterfeit. Viagra, Cialis etc are by far the most counterfeited drugs in the developed world, where as in the 3rd world sadly it is things like anti-maleria (the WHO estimates of the 1M deaths due to maleria in 2008, 200k of them were because the medications that the people were taking were fake), TB and antibiotics.

In short scammers will sell you what you are likely to buy. In the developed world that is "lifestyle" drugs, male enhancement, weightloss, heart meds etc, in the 3rd world it is drugs that are necessary for immmediate survival. Since if you have regular access to the internet you are relatively well off, the spam tends towards the "lifestyle" drugs that are most heavily used in the developed world.