Although VoIP isn’t very popular in the US yet, service providers say adoption is growing (up 20% since last June), and that most users are very satisfied with service.

“About 3.9 million US households used VoIP as their home-phone service in January 2006,” according to a study released Tuesday by Telephia, a market research firm. “That accounts for about 3.5% of U.S. households, up from 2.9% using VoIP in June 2005.” However, the survey failed to include digital phone offerings from cable companies such as Comcast, and Time Warner, which offer “triple-play” packages of television, high-speed data and phone service.
Vonage is the distinct top-dog when it comes to non-cable VoIP services. Vonage lead with a 40% market share last June, and has currently rose to 47.5%. Vonage has nearly four times the US share of its closest competitor Skype, which holds an 11.8% share.

However, market share doesn’t necessarily lead to profitability. Vonage, which announced IPO plans last month, lost almost $190 million in the first nine months of 2005.

Other VoIP providers listed in the market share report include CallVantage from AT&T, VoiceWing from Verizon, and Google. Market share for these providers was 5.6%, 5.0% and 2.5%, respectively.

VoIP’s most early adopters have had the fortune of being content with service quality, unlike the ire of broadband providers, many of which sell their own telephone products. About 86% of respondents said voice quality was equal to or better than traditional phone service. A similar percentage said they considered VoIP to be equally or more reliable as well.