"When you and I engage in conversation, I can’t control how well you communicate; I can only control how well I receive what you’re telling me. I can go on the alert to things that may distort the messages you’re sending me – I call them filters. To be a good listener, you’ve got to know what you filters are. Maybe you’re coming into a given conversation with an agenda. Maybe you’re judging the speaker and don’t trust him at all. Maybe you’re angry. Anyone of these psychological filters can distort what you hear."
This is especially dangerous with "low human bandwidth" tools such as email or IM where you lose all the intonations and non-verbal cues (which led to the need for these silly emoticons). It’s incredibly easy to take an email the wrong way, so there’s only so much interaction you can have through online text-only tools. Even in 100% online-centric projects, the amount of trust required to do business will require partners to work the phone and meet face to face sooner or later (from personal experience, I’d advise sooner than later, it really makes a difference).