consumer voip in the enterprise?

i think this article raises some interesting points:

The materialisation of consumer Voice over Internet Protocol (VoIP) services in 2005 has seen more than 50 million people register for a service across the globe. However, with all the advantages that come with a VoIP service there can be drawbacks when a consumer VoIP service is used in a business environment.

Recent debate about the security implications of retail VoIP services has led to analyst firm Info-Tech Research Group to call for businesses to address the use of consumer VoIP at work. THUS agrees that consumer VoIP services are now causing IT departments considerable concern and highlights the following reasons