Lots of people will warn you about where you leave your address. Many will tell you to get some 'throw-away' ones. But those techniques won't help with your old addresses that all your friends have or that are used by some national organization that only updates info once a year! And it soon becomes as much work getting new addresses as monitoring others.
Others will ask you to forward SPAM to several sites/agencies that track/monitor this activity. Probably won't do any harm, but don't expect fast action.
Of course, you probably know that you should never use the "Unsubscribe" link in any SPAM. But you should also never use any link in one, either - you will probably simply send a message to the server confirming your existance.
My routine is essetially to carefully set up filters in Eudora to look for 'image' tags in the body of a message. This will alert me to anything that will send a message to the authors server when I open that message. The image may not even show up in the message; it could be a 1 by 1, transparent GIF, but it will send a request for that image none the less. When that message is sent, it will be logged on that server and your address will be confirmed as a valid, 'live' one.
Secondly, I don't use Eudora to automatically download any mail - it only downloads when I tell it to - manually. Instead, I use
POPMonitor, running all the time to check my accounts every 30 minutes. POPMonitor does not allow any HTML actions; it simply shows the text of a message. It cannot be used to send anything. But it does have much better filtering capabilities, IMHO, than Eudora.
I still have to add adresses to its 'Blocked' list. But I can do that several different ways and with only one click. It is also great for creating a 'Trusted' list - those messages are marked and I usually don't bother ever reading them in POPMonitor, at all - I just open Eudora and download them when I'm ready.
It also has a 'Bounce' action, but I doubt that the real senders address is in the message that you get. It may help if what you are getting is actually being generated by a virus on someones machine, but even that address is not guaranteed accrurate. I did, recently, get about a dozen messages from the same "sender." I assumed they were being generated by a virus using someones address book. But respnding to anything you think might be SPAM is risky. I always assume that I will eventually be confirming to the author that my address is available and valid.
All the above is doen in 9.1, but I've read that there are many UNIX programs, with OS X GUI's that are very powerful in deleting/marking/handling SPAM. POPMonitor also has an OS X version (only a maintainance version in 9 now).
Jim C.