My work uses it. It is pretty neat. All the telephones are basically switches. You can plug your laptop into them and use the internet off of that. It is a private voice network in which all telephones or devices associated with it is given an IP address, acting as network devices or nodes. The Cisco phones used are very nice and has a lot of custom settings. They use VoIP instead of paying big money though the telephone company. This way, you'll have your own telephone network in your workplace. Useless if you are at home, but benefits greatly in a large work place.
*Fact: Microsoft Window's Blue Screen of Death vs Computerforums.org's White Screen of Death. Which is worse?