Have you heard about the "Internet of things"? It's a relatively new idea to me, although I note that the phrase gets about 2.2 million Google hits (at last count) and it has its own Wikipedia entry and a YouTube clip or two. As best as I can tell, it means that many things -- cars, buildings, the electric grid, appliances, smart phones, cash registers -- could be equipped with sensors, networked and thus able to communicate with one another and, of course, with the rest of us. To bring the concept down to earth, think of RFID codes on supermarket items that tell grocers when to restock, GPS phones equipped with Urbanspoon software that identifies nearby restaurants, or the work of startups like Historic Futures that help companies trace the origins of everything in their supply chain.

Or "smart" parking spaces. Streetline is a San Francisco-based startup that wants to equip parking places with sensors and software so they can to talk to cars and the people who drive them. The company's service is being pitched as a sustainability play -- as a way to reduce traffic congestion, gasoline use and carbon emissions -- but its success will more likely depend on whether it helps cities realize more revenue from parking meters, either through more effective enforcement or dynamic pricing of parking.

Still, for anyone who has circled a block endlessly looking for a spot, the idea has appeal.

"You can stand up in a room of 10 people or 1,000 people and ask them if they have had trouble finding a parking place and just about everybody raises their hand," Zua Yusuf, the chief executive of Streetline, told me when we met recently in San Francisco.

"The carbon impact, the pollution impact, the congestion impact -- it's just been completely ignored," Zia says.

Streetline has deployed what it calls "ultra low power mesh sensor networks" in San Francisco, Los Angeles and Sausalito, CA. What this means is that the company has installed sensors in the ground at parking places which "know" whether a car is parked there, as well as sensors on meters that "know" whether there's time remaining or not.

They can sense whether a meter is broken, too -- information that is not likely to find its way to City Hall by other means. "The willingness to report broken meters is close to zero," Zia says. "For consumers, a broken meter is heaven." All of this real-time data is transmitted to the Internet where can be seen by city parking officials in detail and made available, in a summary form, to drivers.