Here at the Web Developer's Journal, we love both email-based lists and Web-based discussion groups. We've found that they're both excellent ways to build traffic to our site. And since we're an ad-supported resource, traffic is the name of the game. Mailing lists are also valuable advertising vehicles in their own right.
Starting your own mailing list is one of the best things you can do to boost traffic to your Web site, but it isn't the easiest thing in the world to do. The most popular mailing list software packages are Majordomo, Listserv and Lyris. All are quite powerful and well supported, but none are particularly easy to use. If you want to run your own mailing list, you'll need someone geeky on your staff who can figure out how to get things up and running with a minimum of hassle. Also, mailing lists require a certain amount of ongoing maintenance, so you'll need to have a staff member available for that, although once things are set up, not that much technical expertise is required.
If you don't want to take on the project of actually running your own list, there are several services out there that will run the whole thing for you. Some are "free," but require you to scratch their back one way or another, usually by giving them free publicity on your list.
For an overview of how you can use mailing lists to boost Web site traffic, see my article Mailing Lists for Web Sites.
If you want to set up your own mailing lists, see our comparative review of Discussion Group and Mailing List Software.
If you've already got a mailing list, and want some ideas on how to increase the circulation, Webreference.com has two excellent articles that you should read:
Tips for Increasing Subscribers
Newsletter Promotion: Pounding the Pavement and Hitting the Web
