Ask HN: Sending non-mass emails?

Ok, so I know HN likes MailChimp for mass emails...

But what do you guys use for single email sends? I'm talking about stuff like email verification emails, or notification/unique emails that are sent to a single user through normal web use?

I have dealt before with setting up my own SMTP server, configuring the different anti-spam configurations different recipients like (SPF, etc). Then going through hell with blacklists and a-hole sys admin policies in order to get the emails to go through.

A small site can use something like a gmail account to send outbound emails, but I figure Google is going to get pissed off and block the account soon.

So what does HN do for this task?