Autonet Mobile, the pioneering provider of Internet service in automobiles, grew substantially over the past year, with revenue more than tripling.

Meanwhile, interest in the space among automakers and equipment manufacturers has spiked, judging from the flurry of announcements around the “connected car” that emerged at this week’s consumer electronics show in Las Vegas.

“We’re seeing this whole ecosystem unfold,” said Autonet Mobile CEO Sterling Pratz, who co-founded his 28-person San Francisco-based company in 2005.

Pratz said revenue is now running at an annual rate of more than $3 million, up from roughly $1 million at the end of 2008, and the number of customers is expected to cross 10,000 by the end of the second quarter, up from about 3,000 a year ago.

Autonet Mobile sells onboard modems that use proprietary technology to avoid signal interruptions, and it provides mobile WiFi service for a monthly subscription fee starting at $29.

The company plans to announce new services at next month’s Chicago Auto Show, including the ability to “geofence”—a subscriber can get an email if their vehicle leaves a designated area and will be able to locate a vehicle to within a few feet.

Such capabilities will put Autonet Mobile in competition with LoJack, which helps find stolen vehicles using radio transmitters, Pratz said.

Autonet Mobile also recently signed a distribution agreement with a new automobile manufacturer, Pratz said, although he would not give a name. The company already has deals with General Motors, Chrysler Corp., and Volkswagen and Delphi Corp., the giant, Michigan-based automotive electronics manufacturer.

To accommodate increased demand, Autonet Mobile last year opened an operations center in Detroit in addition to the one it already operates in Santa Rosa, Pratz said.

Industry interest in bringing the Internet into automobiles, meanwhile, was strongly in evidence at CES in Las Vegas, where Pratz was a featured speaker. Ford Motor Co. was showing off its second-generation SYNC system, which lets users get Internet service using wireless cards.

Oakland, California’s Pandora Media announced an automobile-tailored Internet-radio application. The giant Visteon Corp. of Michigan was showing off a platform it said would connect cockpit devices and infotainment devices to the Internet, allowing for synchronization with home devices. NetLogic Microsystems of Mountain View, California, was touting new chips it says will optimize in-vehicle infotainment devices as well as vehicle operation systems.

And new multi-industry association called ng Connect, with members ranging from Alcatel-Lucent to Toyota Motors, was also demonstrating a new wireless broadband technology called Long Term Evolution that it claims will dramatically improve in-vehicle Internet service.

“The more that jump in, the merrier,” said Pratz. “Our sales go up every month. They don’t go down.”