With co-registration, you advertise your ezine along one or more other advertisers. A prospect can then sign up for one or more ezines at the same time.
You can set this up as a joint venture (free) with one or more ezine publishers or use a co-registration service (paid).
If you go the JV route, you will have to set up a custom script on your own web server, and your JV partners would do the same. There are many options available to you, simply search the web, or have your web master set it up.
If you’re not technically inclined, or do not have the time to look for JV partners, I recommend you use a co-reg service. In a day or two you can add hundreds of new subscribers to your list!
Simply put, you sign up with a service provider who then places your ezine ad on their web site. You sign up to buy a certain number of subscribers. I use ListBuilder and GetSubscribers (the latter only works with GetResponse, a highly-recommended Auto-Responder and Email Service Provider).