List Building Secret #17 - Thank You For Subscribing Page

Simple enough. Get a group of publishers together and tell them you want to send new subscribers of your ezine to a page that recommends signing up for their ezine and that they do the same.
You see it all the time. You subscribe to an ezine you see on a website and once you subscribe you are taken to another page that recommends other peoples newsletters that you should join.
This is pretty much a localized version of co-registration, but it costs you nothing.