Low-latency email carrying is awesomely variable. It's asynchronous, and I can reply quickly if I want to. If I don't want to (such as if a fast response is mor

Low-latency email carrying is awesomely variable. It's asynchronous, and I can reply quickly if I want to. If I don't want to (such as if a fast response is more a waste of time, or encouraging unnecessary queries), I can hold off for an hour or two without annoying most people. I've been accused of turning email into instance-messaging, if the email service is low-latency enough. GMail's typical turnaround for me is under a minute, sometimes under 30 seconds, if the response doesn't need to be extensive. (It usually doesn't.) Thanks to presence notification and expectation of synchronous communication, IM tends to be very synchronous, and almost as draining and disruptive as phone calls.