Why is Viagra spam profitable?

When it comes to advertising, the art is far from an exact science. Big companies spend millions on advertising, and big companies don't usually spend millions without good cause. And yet, perhaps surprisingly, no one can ever really be sure how much a particular advertising campaign is doing, because it's nigh-impossible to separate its effect from other things going on in the market. There simply aren't control groups. But there are some approximations -- advertising in one town and not in another comparable one far away -- that have convinced companies it's worth pouring money into advertising.

A lot of those analyses fall apart when you look at spam. Once you get into the spammer market, the costs to continue in it are minimal. The whole problem with spam is that even the nominal costs of printing and postage, or other distribution methods, which normally put some kind of cap on how much advertisers can blanket a market, don't apply. Almost all the cost of email is paid by the receiver, not the sender. But there is some cost, so there has to be some revenue to make up for it. You don't need to get one out of a hundred, or a thousand, or maybe even a million, to catch up, but you do need some.

So who the heck is responding to the endless parade of Viagra spam? Do those spams actually even contain enough information to purchase from them if you wanted to? How are these people staying in business? It boggles the mind to imagine that someone, somewhere, is getting the ten-thousandth of those spams today and this time is going to say "Hmm, I wonder," and follow a link somewhere in there, and instead of getting malware (or more likely, in addition), he gets to a form where he actually enters his credit card information. (I have to assume the odds that there's actually Viagra purchased are slim even at this point; more likely, he's signing up for credit card fraud or identity theft, which are probably more profitable. But some of them actually go to Viagra sales somehow.)

If only we could stop there being another him today, the spam itself would dry up.