Changes in a number of areas are transforming business telephony. These changes have varying causes: advances in IP communication technology, the explosion of mobile communication, the growth of cloud-based services, and the proliferation of video conferencing, to name a few. The changes have affected small companies in big ways. In particular, they have given SMBs access to communication capabilities formerly reserved for large companies. But they also have growing potential to affect enterprises. Thus the failure to keep on top of them can leave even the biggest companies at risk of falling behind.