I've had yet another person get stuck with a spammer using their contact list and sending spam task though they were the person. It happens so much, and the Internet seems to have so many different answers, I figured I'd send this consolidated list over to him, and share here. Short answer A few big spam companies get your email list from finding the email addresses of your friends on Facebook that publicly list their email address. They also get it from forums you post to, your blog (emails are often listed there) and forwarded messages from someone else. Those spammers then sell the email lists to other people. Change your password often. It’s not foolproof, but is a good idea. Also make your email password different from all other passwords you use on the web. When registering for sites, use a throw-away email address and some password. Or make your current email a throw-away and make a new email account that you tell your friends to use (I made my Yahoo a throw-awa...