I seem to have been involved in quite a few discussions about spam lately, so this is perhaps a good time to collect up some of my thoughts on the subject.
Surely spam only matters if it is delivered to you?
I think you just have to see spam as 'noise'.
In my view things have improved markedly over the last couple of years. As with anti-virus, the need for spam handling is accepted in the industry, as is the probable need to spend money on it. Assuming an organisation has something in place, its end users should be able to ignore spam because they actually hardly ever see any. The old worry, that anti-spam measures mean proper emails get lost, does remain to some extent, but there are plenty of R&D dollars in the anti-spam industry now, and I would personally say they are nearly as much on top of the problem as the anti-virus vendors. When did you last get any spam in your business email account? I get hardly any even in my hotmail account these days. The legal sanctions, especially those imposed by the EU, do help - in the U.S. spammers are harder to deal with because the anti-spam law has less teeth. In summary, there's more and more spam out there, but if you put an intelligent product or service in place you really ought to be able to ignore it for practical purposes.
What are the spammers trying to achieve, and how do they do it?
There are three types of entity involved: the more or less criminal, stupid and/or misguided entity that is trying to sell its services or to defraud people; the intelligent and criminal entity that undertakes to send out spam on behalf of the first entity, and which uses completely dodgy techniques to do it; and the entity that actually transmits the spam, probably without knowing anything about it through its accidental membership of a botnet managed by the second entity. (It's almost certainly only the second of these that makes any money out of the enterprise.)
Incidentally I am frequently amazed by the appalling quality of the product - I've often thought that someone with a modicum of common sense, reasonable grammar and spelling and some commercial nous could actually achieve a lot more than these people do ... let's be grateful for small mercies.