All you need to participate is an e-mail address. You join an email list by "subscribing" to it. This doesn't mean you have to pay money; it just means you are asking to have your email address added to the distribution list. To subscribe, send an email message to the list administrator who adds your email address to the list. You'll get a reply that gives you all the details you need to know about the list and how to participate. Soon, you'll start receiving mail from other list members.
NOTE: Be wary of sites to which you give your email address. Some sites will sell or give your email address other sites, who in turn could pass it along again. Before you know it, you can be receiving email from many different sites that you have never even visited. Many sites have a Privacy Policy explaining what they will do with your email address. The more reputable sites will not sell your email address and will keep it totally confidential. - Updated: March 18, 2002