Newsletter platforms: please support 1-click subscribe

That would be a concern for auto-importing the addresses into the promoted newsletter (obviously you don't want to just expose an endpoint that says "POST an email here to bypass captcha and confirmation email!"), but for the first half of the problem (allowing the promoter to know who clicked the link), I'm pretty sure it just hasn't been prioritized. Mailchimp already supports web hooks for click events.

Once that side is taken care of, importing could be done between trusted parties, but yeah, might need to address that in the ToS/privacy policy first.