Peter Davis from XO and I walked around VoiceCon 2010 in Orlando asking people what UC means. The answers were all over the map -- and some off the map.
UC is not one solution. It is a number of pieces that can be put together in respond to business needs.
Not everyone is a knowledge worker or a customer service rep, so not every worker needs the full boat of Unified Communications. Luckily, you can deliver a solution to a business tailored to each worker. That's the flexibility and benefit of UC.