I think the point is that your mom wouldn't have to do anything. One person -- presumably the one who is good at email but frustrated that everyone else isn't,

I think the point is that your mom wouldn't have to do anything. One person -- presumably the one who is good at email but frustrated that everyone else isn't, e.g. You -- sets it up and pays and just sends their very next email to 'the group'. And everyone else just responds to that email as they would any other and it Just Works for them, regardless of whether Mom chronically forgets to "Reply All" or Dad never remembers to put Aunt Sally on the list. I'd imagine people who don't email a lot with less-tech-savvy types probably don't see the advantage. And it really does sound like a 'feature' that any mail host could add at any point. But if it gets traction and other mail providers match the feature, that's a win for everyone, right? I doubt 37signals has big plans for the revenue from this service. They're likely just solving their own problem and charging just enough to cover the administrative overhead and dissuade spam use.