It's difficult to pinpoint all the profound societal changes that mobile communication has triggered. But it is clear that the ability to send and receive email at any time and nearly any place has greatly shifted many norms.
Where there was once a cut-off in calling a friend or colleague or client, now Blackberry-powered email enables communication without limitation. I believe that this is particularly important for most service industries. If there is a professional serving a client, no longer is the time-of-day an acceptable excuse for a lack of communication.
I see many trying to cling to the old 9 to 5 (or 7 to 7) standards of the past. This just isn't going to work for much longer. As more and more digital natives (like myself) become both providers and consumers of services, the old rules will fade. This means that new rules for accepted behavior must be outlined and accepted - both locally and universally - and especially within teams of individuals that come from different generations.