Most spam messages are in no doubt worthless. It's all stuff that's too cruddy to be worth advertising in any medium where they'd actually have to pay the cost of the ads. Also, since the cost of spamming is so low, there's no point in targeting your ads, when for the same low price you can send the ads to everyone, increasing the noise level the rest of us have to deal with. Spam software invariably comes with a list of names falsely claimed to be of people who've said they want to receive ads, but actually consisting of unwilling victims culled at random from Usenet or mailing lists. Spam software often promises to run on a provider's system in a way designed to be hard for the provider to detect so they can't tell what the spammer is doing.
Spams invariably say they'll remove names on request, but they almost never do.
In some countries spamming is illegal. Especially with pornography, mere possession of such material can be enough to put the recipient in jail. In the United States, child pornography is highly illegal and we've already seen spammed child porn offers. Any one of these six would be enough to make us pretty unhappy about getting junk e-mail. If you would like more information on how to combat spam.