One thing that seems to be missing from this implementation is an easy way to unsubscribe.
I send the newsletter from a monitored account so people can reply unsubscribe (and I put a reminder in the top of the newsletter). You're probably right I should have a better system. It seems any one click unsubscribe link would require me to send a slightly different e-mail to everyone which I'd rather avoid.
Typo in paragraph starting with "Side note". "most" -> "must"