The ability to massmail your buddies you have as contacts would be pretty convenient. Although this ability may be abused it can be countered with the ignore button.

There was going to be a mass mail function within contacts but I guess the admins changed their minds due to the fact it could easily be misused. A spammer could simply copy the past few minutes list to a contact group and mail everyone currently online.

I still like the idea of this. Perhaps a mass mail contact would be required to give their consent, otherwise you couldn't do so?

I was under the impression this was still in their plans, I just don't know when they planned on doing it.