[encoderer]

Which is why double opt-in is the only way to run a list if you truly care about marketing with permission.

Respectfully, I think you are entirely wrong: the two options are VERY dissimilar. In one case, you send them a single "Click here to confirm" email -- and maybe a single follow-up a few days later.

In the other case, you're continually marketing to them and putting the burden on the recipient to opt-out, usually in tiny text at the bottom of the email.

[shabble]

and on top of that, the last thing you want to do for many actual spam lists is to click their per-address unique tracking tag which tells them that your address is valid.

If you've already started communicating with them I guess it's probably reasonable to consider it 'blown' anyway, but I'm always extremely dubious of opt-out/unsub links for that reason.