I've been thinking about this a lot. Somewhere I heard, and I wish I could remember where, that the average time for a person to get their first response via Yahoo Answers in Korea is 45 seconds. That's a remarkable response time when you realize that the answer is most likely being typed on a mobile phone. Now, that answer is most probably crap, but the point remains-- in this new world people have an expectation of an almost instantaneous response. If you aren't prepared to offer instantaneous service then you shouldn't attempt to offer the service at all as you are most likely going to disappoint.