Here is a highly effective method for responding to spam, I call it "respamming". In each case the idea is to use up spammer resources so that it is not profitable to spam. If the spammers get a profit from 0.1% of their spams, but 1% of the people object, then they will be forced out of buisness. That means that each person would need to do this only once for every 100 spams for it to be effective. One can treat it as an interesting hobby - how many spammers can one get kicked off the net?
The principle is that all spam has a fuse that leads back to them by which they can be undone. There are a number of possibilities for what to do in various cases.
Non commercial, no return address. Use spamcop.net to identify and have their ISP cut them off. This can be used for any spam, and can be quite effective.
Phone. One can call the number and object to the spam. This ties up the spammer's resources, blocking them from contact with customers. One might be able to automate this with a computer.
Web - Credit card. One can follow the links to their back to their web site. If the only way to send them information is along with a credit card number, you are at a dead end unless you are willing to risk some money to attack them. In any case, use Spamcop.
Email. If there are email addresses at the web site then the fun begins. The theory is that they already have your email address, so sending them email won't make a difference. Under Unix (eg, Linux and Mac OSX) you can write a script that will send mail to all of the addresses using a simple loop and the standard mail program. You may choose the number of messages to send. I suggest being very polite. Usually the spammer will go belly up if they receive 256 or 1024 emails, and politely ask one to stop. In some cases one can get them to tell the name of the email list. This is respamming. Do not do this without permission of your systems administrators.
Web. If there are no email addresses, but there are web forms, one can fill them out with garbage (do not use self-identifying information unless you want to) that includes a strong but polite objection to the spam. One may backspace and repeatedly send the form until one is satisfied that they have gotten the idea. Alternatively, one can use wget to automatically fill out the form hundreds of times. In theory one can fill their entire disk ... An example from the "indecent proposal" category is http://www.pillsmedical.com/support.html.
Visit. If the spammer is local, one can go to their offices and lodge a complaint directly to the president of the organization.
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