@cyberus
Spammers are paradoxical. The best I can tell it that they have no interest in what the address is or if it is even valid. They either get paid by the amount of ads they send, or how many people respond. The second one is more logical for the people who pay them to spam, so that's probably it.
If spammers cared about valid addresses, they wouldn't be sending emails with spoofed return addresses. They avoid complaints that way and since they also don't get any "this address does not exist", it can only be assumed that they don't care about valid addresses. Email is free to send, so sending a billion emails costs them nothing and is probably only one click on their computer.
I'm sure that these fake "click here to remove from our list" things are just a way to get you to respond so they can get paid. Your address is already on their list. They don't want to confirm your address is valid, they just want you to respond for their billing records. Ten percent of people respond/buy from spam and ten percent of a billion is quite a lot.
The only real way to get rid of these punks is to go after the people they spam for. But, those guys are probably not too honest either and will just move to a different motel to work out of if anyone investigates.
