Lots of talk about unified communications this week, thanks to Microsoft. But what CIOs really need to know is which feature will cause fellow execs to utter these words: "For that feature alone it's worth doing this system." I've got two examples.Twice I can remember CIOs using exactly those words to describe what their colleagues told them about different features in their newly implemented unified communications and voice-over-IP systems.

One CIO, of a health-products distributor, cited voice mail that shows up in an e-mail in-box. That lets people listen to the v-mail from their boss before the one from their dry cleaners. (We've got a review up this week of services that let you do this.) Colleagues stopped him in the hall to say how much time it saved them.

The other, of an accounting firm, pointed to what I guess you'd call extension portability -- letting someone visiting the Chicago office answer the phone as if they were still back in the Detroit office. Given how much these professionals traveled, and their desire not to make clients have to track them down, it was a godsend.

These "for that feature alone … " moments are so important because they tap into emotion. No CIO will build an ROI case for unified communications on one feature, and they'll all dutifully work up a rigorous business case before proceeding. A lot of these tend to depend on cutting the phone bill (and at times ignoring that echo from the end of a poorly managed VoIP line). If unified communications is going to really make a difference, though, it will be immeasurable, by delighting employees in ways like these, where people simply can't imagine going back to working without it.