Ask HN:When to expect reply to emails?
CyberFonic: You don't say whether you are talking about people whom you know or happened to have come across in a forum, or some such.If you e-mail people you don't know (well) with questions then you run the risk of the RTFM / Just Google It! reaction.  For CS questions, might be an idea to have a look at StackOverflow and/or ServerFault and if not already answered, raise the question there.  The more knowledgeable people are also the more time-poor and more likely to be irritated by people asking questions without having a go at finding the answer.As for people whom you do know well, well you can always ask them.My general response to people asking why I didn't respond to their e-mail quickly (and that's a subjective thing) I just say "If it's urgent, pick up the %#@&* phone".