Via Forbes:

Few American households use voice-over-Internet Protocol (VoIP) services as their home phone but adoption is growing — up 20% since June 2005 — and most users are satisfied with their service.

About 3.9 million U.S. households used VoIP as 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 didn’t include digital-phone offerings from cable companies like Comcast (nasdaq: CMCSA) and Time Warner (nyse: TWX), which hawk "triple-play" packages of television, high-speed data and phone service.

Of the non-cable VoIP services, Vonage leads the pack with a 47.5% market share, up from a 40% share last June. Vonage had almost four times the U.S. share of its closest competitor Skype, a unit of eBay (nasdaq: EBAY), which placed second with an 11.8% share.

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