There are number of reasons to like email based direct marketing. Sure, its cheaper than dead tree direct marketing via snail mail... and yes, it suffers from the same problem as UCE in the form of costing those receiving it some amount (very small, but not zero) of money. Having read David Brin's Earth[amazon], I personally can't wait for the day when non-package postal delivery goes the way of the dinosaurs, and that goes double for the vast majority of dead tree junk mail, some large percentage of which ends up in our land fills without doing anything useful except pay for the postal service itself. That's my way of saying that email based direct marketing is more environmentally friendly... and easier to ignore and get rid of.
The problem with SPAM is that it drowns out the more legitimate direct marketing. How many viagra/university diplomas/mortgages/stock scams/diet scams/etc do I delete on a daily basis? And do the people who send those things actually enjoy their work? The 500th time the university diploma idiot figures out a way around the Yahoo! Mail spam blocker to spam all of those accounts again... does he get that many responses to justify what he's doing?
And the relatively new crop of supposedly "opt-in" lists... which I appreciate because I can more easily filter them, but they are merely capitalizing on the fact that so many web sites these days add you to one marketing list or another during registration that maybe, just maybe, people will actually believe them. Just more crap to be deleted...
Combine this with all of the legitimate marketing email... I now get about 10 messages a week from various airlines or ticketing websites that I actually signed up for... and where is the space for the few offers that might actually be useful?
One possible solution is IronPort's Bonded Sender program, of course. It would help eliminate the junk bulk mail and allow through stuff that people in theory want... but it won't solve the problem of what happens when every vendor you've ever registered with wants to send you marketing material on a frequent basis. I'm not sure what the solution to that is... but I guess I'm going to be adding to the noise.