Jupiter Research projects that the broadband telephony market will nearly double in size from 14.7 million subscribers in 2007 to 28.4 million lines in 2013. Cable operators will see most of this increase, with their VoIP subscriber base nearly doubling during the forecast period, while growth for over-the-top VoIP providers will stagnate. The emergence of new service offerings, such as those from AT&T and Skype, will continue to generate buzz within the market.

According to a new JupiterResearch report, "US Broadband Telephony Forecast, 2008 to 2013," cable multiple system operators (MSOs) have maintained momentum in the voice service market by continuing to focus on competitive triple-play service bundles. Of consumers who subscribe to a cable MSO-managed VoIP service, 47 percent said bundling had a strong influence on their selection of home phone service provider.

Despite having a moderate impact on the VoIP market overall, the emergence of AT&T's U-verse Voice is an important market development.

Looking ahead, JupiterResearch observes a few wild card scenarios that could shake up the market for broadband telephony, namely the potential for Verizon to migrate all services including voice within its FiOS bundles to an IP platform, as well as new product offerings such as the Skype phone, which de-couples Skype's voice chat service from the PC, and T-Mobile's new "@Home" over-the-top VoIP offer for $10 per month.