Is VOIP a threat for telcos?

Forrester denies VOIP will be a threat for telcos that will adopt IP technology, such as BT. The main rationale behind is that pure VOIP service providers will be unable to provide differentiated services, and will have problems to stay alone. Forecasting that customers will only progressively adopt VOIP (1% of current traffic, 30% in 2010 and 100% by 2020), it will give time for telcos to adopt the VOIP technology. Forrester also denies VOIP will bring free calls forever, wisely saying someone has to pay for the service.