According to Analysys forecasts, by 2008, VoIP penetration is expected to reach 17% of broadband-enabled households (growing from under 1 million at the end of this year to 11.7 million in 2008), and 23% of broadband-enabled small-business establishments (increasing from less than 100,000 in 2004 to 800,000 in 2008). Together, consumers and small businesses are expected to provide almost 13 million VoIP subscriptions and USD5.7 billion in annual service revenue in 2008. Although this is a significant amount, it represents 2.5% of the 2003 total US telecoms revenue of USD224 billion.
For medium and large businesses VoIP growth is also very strong. Analysys expects the estimated installed base of IP station lines to increase from just over 3 million in 2004 to more than 18 million by the end of 2008. This represents a compound annual growth rate of over 50%.BusinessWire: VoIP is a Turning Point for Us Telecoms, Says Analysys
See that? 2.5% of the total US telecom revenue. That's a lot of headroom. I still find the medium business space more interesting.
(via Andy Abramson VoIP Watch)