Everyone knows the best way to build a mailing list is to give interested parties the opportunity to sign themselves up to receive mailings from you and your business partners periodically.
Apparently, not everyone knows the best way to burn that list. If you want to burn your list quickly, send out a slick little email with a very professionally done, hip postcard image promising more information on the website, but make sure the website has no information at all. Not even an update or change from when the user first used the website to sign up for the mailing list.
Good mailing lists are hard to generate and should be treated with kid gloves. A quality list developed from information that you’ve collected from users, visitors and customers is much, MUCH more valuable than anything you can buy from some third party.
Respect the fact that people have trusted you with their personal information, and when you exercise the privilege of contacting these trusting souls be certain you’re sending them information or offers that are actually going to appeal to them. Otherwise, you’ll find your carefully cultivated list evaporating into nothing.