[paraschopra]

>you can not send emails (you can receive them).

Seems like a deal-killer to me.

[mahmud]

Not at all. If you're using email as notification, move your MTA to another port, or use something else.

[loup-vaillant]

Not being a spammer doesn't mean you don't want to send your e-mail from a machine that you control. If you want to do just that, a closed smtp port is a deal breaker.

If you're happy to have Google send your e-mail for you, or control another machine that does that job, you're not in the same situation, of course.