Take your email address out of your web browser
Be aware of what information you’re providing to whom
Don’t provide personal information—including your email address—to any web site unless you would want to receive email from them. The same goes for any information requested in the meat world—I see more and more response forms requesting an email address if you have one. Some of the sites that do require that you enter an address have a selection box where you can note that you don’t want to receive email from them. You can make sure you tell them you don’t want the email—or you can just enter a bogus address in the first place (again, make sure that it couldn’t be anyone else’s valid email address). I will warn you that I worked briefly for a company that provided information services to a large retailer with an excellent reputation, and was surprised to find that they included every customer whose information they had in mailings, without regard to the “I don’t want to get mail from you” requests. After that, I decided that no company needs my email address unless I do business with them online.
Use different email addresses for specific purposes
Some people, especially those who own their own domains, use different email addresses every time they provide an address to anyone. If they register to use Microsoft’s tech support site, they’ll use one address for that. They’ll use another address as a contact point for an account with Amazon, and a third to register a Salon, and so on. They keep track of which addresses they used where, and if they start receiving spam at those addresses, they know who is selling the address to spammers. They can then chose to delete that particular email address and not do business with the offending organization again.
Don’t trust a web-based postcard site that isn’t an established, respectable company—and ask your correspondents to do the same