craschworks

In person, or on the phone, you can tell if you're interrupting, or if the person wants to move on to other things by their posture, and voice inflection. Feigning unconsciousness, blowing bubbles, and yelling “Get the HELL out of MY OFFICE!” are also effective. When IMing, you don't have these options. Well, that last one is available, but it just doesn't seem polite.

When IM'ing, I assume that the other party will tell me “Hey, I gotta go.”, or simply not answer if they are busy. However, it sometimes feels a bit awkward. For example, if you've sent something, and the other person doesn't respond, how long do you wait before you assume a) they're blowing you off b) they've been distracted by other work c) they're thinking of a response.