[ebbv]

The usual way home computers get compromised is user error; downloading and installing software that they shouldn't. It's social engineering. "Your computer has a virus! Install our software!"

Also running a home email server isn't usually that helpful. Even if you do that you're going to have to use relays to get your message where you want it to go (unless the topology of internet email changes dramatically), so you might as well cut out the step of having your own server and just send the mail directly to the first relay you'd be using anyway.