Although I can see where the behavior John speaks of occurs,{another person feeling like they are not being heard}however, I have found for the most part that such behvior, being ignored, is due to shear Rudeness and has nothing to do with lurking. Lurking, in my opinion, means to watch others interact in an non-distruptive manner, so that the pace of the environment goes undisturbed and as "naturalistic" as possible. Given this premiss, it is the lurkers responsibility to respond when spoken to, and also to help those other individuals (non-channel members) who wander into the (your) lurking environment the opportunity to be "heard" It would be no different than having a stranger walk into your office/class/meeting, you would acknowledge their presence, to do otherwise would be to ignore them purposefully, and that is plain Rudeness. Lurking, talking, thinking... each has its own place, respecting them in ourselves and others should be the guidelines by which behavior, and therefore interaction between individuals, occurs.
Thanks for the forum...