Interesting article from the Detroit Free Press suggests that small businesses can use VoIP PBX systems to create a larger apparent presence:

For example, you can boost the legitimacy of your business without investing thousands in a private branch exchange system by looking at a cheaper alternative, such as a hosted phone system, said Harprit Singh, president and CEO of Intellicom Inc. A private branch exchange, or PBX system, is a telephone exchange that serves a particular business or office.