I always preferred IM or email to phone or face-to-face for this exact reason. IM and email can be ignored until its convenient to reply, but phone and face-to-

I always preferred IM or email to phone or face-to-face for this exact reason. IM and email can be ignored until its convenient to reply, but phone and face-to-face forces you to stop working and respond right away, even if you were right in the middle of something.