Presence awareness isn't perfect, (at least not in any implementation I've seen so far,) and that doesn't prevent the PHBs from "leaving a message." When they do so, of course, they expect that the user deal with that issue right away, with no regard to that user's workload, other duties or responsabilities.
The UC articles have seemd to be asking "do you use UC, if you do what parts of UC do you use, and why? What parts don't you use, and why? What is the overall impression by people at all ends of the stack about the benefits or lack thereof of UC?"
My point here is not that UC can't be a great help...in many environments it certainly can! (I would die without MS Communicator.) The point instead is that beyond managing technology, we have to manage EXPECTATIONS. Every time I have seen UC rolled out, or even contemplated, it is being driven by managment. The driver for them is "more instant than real time" ability to bother someone. There seems to be an honest expectation amongst those asking for UC that it will deliver an ability to have the same people do more in less time, simply because they can be pestered more often by PHBs.
When used properly, and brought in for the right reasons, and with the right expectations, UC can be a boon. The issue is one of...hype, I guess. The perception that seems to have grown in the managerial class of our society that the ability to reach out and taser someone about something makes it occur faster. When unrealistic expectations like that exist but can’t be met, the perceived benefits of UC vanish.