I believe almost everyone who knows how to complain and is willing to do so is already complaining. Since so much e-mail is being discarded unread, most people are no longer willing to take the time to write thoughtful, informative, or entertaining messages. Also, people often hide their addresses, which also cuts off communication. I've often spent an hour replying to someone's posting, only to discover that they posted with a fake address, and there's no way to deduce their real address. It's very much like the effect of crime on a neighborhood.
People surrender their parks and sidewalks, and stop trusting people.
Quite aside from the lost opportunity cost when this wonderful communications medium is rendered almost unusable, the direct costs of spam on recipients are certainly well into the billions of dollars. There are lists of up to 80 million e-mail addresses available. And several spammers who reuse such lists weekly. I heard Sanford Wallace and Walt Rines repeatedly lie under oath at the FTC hearings last year . As far as I know, no spammer has ever even made minimum wage from spamming.