Maybe this varies by area, but professional etiquette everywhere I've been is that you ask before taking an online conversation to the phone. If you're having a forum or email discussion with someone, it's not typical practice to look up their phone number and call them up. For example, I think it would be at least somewhat weird to call someone who posted a StackOverflow question or response, rather than responding to them on SO.
I don't disagree with you about professional etiquette, but to the extent that this is a forum about entrepreneurship, surely we might permit, or even encourage, not to mention applaud, a slight nudging of the boundaries?
