For most people it'd probably make much more sense to find a provider
offers some form of SMTP relay service. It'd probably be cheaper/month,
and they wouldn't have the trouble and expense of providing/maintaining
a colo server.
Yep, if you aren't technically inclined that is better.
What if the cost were only $10/month and they didn't have to maintain
anything other than a set of usernames/passwds (SMTP Auth) or perhaps a
list of their own IPs (relaying based on IP)?
It's starting to sound like a nice little business for a college senior
to set up using one of the colo providers from Paul's list. It would
be a lot more palatable for large providers to crack down on
unauthenticated SMTP if there were such alternatives available. Then
instead of cracking down on users they would be supporting new
small businesses. I imagine there are a lot of people doing this
already but we just don't see it because they don't have a catchy
name for themselves like "ISP".