1/29/2007 -- 2006 might well go down as the year in which voice-over-IP (VoIP) arrived -- on the consumer side, at least.

For starters, U.S. demand for VoIP services increased dramatically last year, with nearly 4 million new households coming online, according to market watcher In-Stat. One upshot of this, In-Stat says, is that wholesale VoIP revenues are growing quickly, as MSOs, Skype and other competitors -- most of which lack network facilities of their own -- enter the market and gin up demand for VoIP-based telephony features and applications.

"As retail VoIP expands, wholesale VoIP will accelerate quickly," said In-Stat analyst Bryan Van Dussen in a statement.

VoIP demand is still greatest among international customers, In-Stat says: "The largest segment remains international VoIP, but we expect the market for local services to surge from 12 percent of all revenues to 27 percent by 2010."

Elsewhere, In-Stat reports, expect increased VoIP adoption among consumers to drive wholesale VoIP revenues much higher -- possibly reaching $3.8 billion by 2010. That's an increase of 345 percent from last year, when wholesale revenues crested at $1.1 billion. At the same time, In-Stat says, international wholesale VoIP termination and/or origination revenues are declining. --Stephen Swoyer