After I wrote a column about how to reduce the amount of spam (junk email) in Google’s Gmail, Don Wenig of Tucson, Ariz., voiced the frustration of many email users.

“I just wish I knew how these creatures got my address,” Wenig said.

I took that to heart, and here is a list of the ways that spam producers get your email address and what you can do to prevent it.

•  Don’t respond to an email from someone you don’t know, not even to “unsubscribe” from an email list that sends you unwanted information. It only confirms that your email address is a good target.

•  Don’t download any email images that weren’t initially displayed by your email program. That also confirms that your email address is available to spam.

•  Don’t sign up for any online service that says it will remove your name from spam lists. Chances are, the site is run or monitored by spammers.

•  Don’t respond to attention-grabbing emails, such as a “delivery failure message” for an email you didn’t send, or a message that says you requested something that you didn’t. They’re just bait.

•  Don’t let an automatic email response go to everybody. When on vacation, set your email to respond with an “I’m-not-here” message only to emails from people already in your contacts list. Otherwise the automatic response may confirm your email address to spammers.

•  Don’t be fooled by phishing emails that urge you to use an email link to a website where you can correct or confirm something about your email, bank account, credit cards or other personal material. These people are trying to steal your personal information.

•  Don’t participate in online contests that offer cash prizes or free trips in exchange for your email address. This is a bit like giving out your street address and telephone number whenever you buy a lottery ticket, something most people would never do.

•  Don’t use your main email address in online forums. Spammers scan these forums with programs called “Web crawlers” that copy email addresses (typically they copy anything that contains the @ symbol.) Protect yourself by adding phony details to your email address, such as inserting the phrase “delete_this” in the middle of the address. You won’t fool any people, but you might trick an automated Web crawler.

•  Don’t give out your real email address without considering two alternatives. You can set up a secondary free email address to give to websites; if that account becomes clogged with spam you can close it. Or set up “disposable email addresses,” temporary addresses that forward email to your real address. See www.tinyurl.com/youhjr/.