Well-written page! There are so many providers who don't bother to try to educate their users as to the pitfalls of unethical list merchants... and then their users just end up getting canned for something they were clueless about.
Personally, I'm a militant confirmed opt-in advocate... While you may want to refrain from requiring opt-in conformation, I think you should mention it on that page as being the optimal way to administer a mailing list, and why. Get users moving in that direction. Explain that if people start reporting them for Spamming, the only way to prove that the address was subscribed voluntarily is to record an audit trail. And explain that a true closed-loop system, using a unique token generated by the subscription server, is the surest way to prove voluntary subscription. In other words, you have a much better chance of keeping your account if you use fully-documented double-opt-in. Anything less, and there are more risks. Of course, even a user who uses double-opt-in can get sacked if they refuse to remove people...
Hey! Here's an idea-- [color=#CC0000]Why don't you guys provide a double-opt-in mechanism in a pre-packaged CGI?[/color] That would be extremely cool of you... As a matter of fact, I don't think I've ever heard of another host that offers one; you could be the first!
The CGI would be in two parts; first, the subscription form, which mails out a confirmation message to the subscribed address. This part of the script could also generate a unique token and store it in a MySQL database; the unique token would be included in a URL sent in the confirmation email.
The second part would process clicks to that URL and add the token and an IP address to the database, confirming the closed loop subscription.
Another option would allow subscribers to reply to the confirmation email to complete the subscription, but that would require the use of something like ProcMail, so the first option would be a lot easier for setup and maintenance.
Naturally, all of this requires an account that offers MySQL...
What do you think, sirs?