Trying to solve a messaging overload problem by making it easier for people to send and receive messages is like trying to solve traffic problems by building more roads. When cities build more roads, more people use them and they quickly get just as congested as before.
Unified messaging is overhyped and poorly understood.
High expectations were set early on, and these expectations have not been met. Unified messaging products are complicated to develop, encompass a range of technologies from different industries, and require acceptance from skeptical customers who are used to buying separate products for each of their messaging needs. Unified messaging will be expensive to buy, install and maintain. Training and significant mind-share from senior management will be required. The more options unified messaging has, the more time it will take to train users, resulting in a slower adoption rate.