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 for you.
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 people’s newsletters that you should join. This is pretty much a better version of co-registration, but it cost you nothing.
