By Charles Wardell. The Web-enabled concept appliances that GE and Whirlpool displayed at the International Builders' Show three years ago have been the butt of lots of jokes. Meanwhile, appliance networking has quietly gone mainstream in Europe.

Merloni, one of Europe's largest appliance makers is successfully selling connected clothes washers, dishwashers, refrigerators, and ovens under the name Ariston Digital. They don't need an Internet connection. Instead, they send data over the power lines using a communications protocol called WRAP (Web-ready appliances protocol). The peer-to-peer network doesn't need a central server.

What do they do? San Jose, Calif.-based Echelon Corp. has been supplying Enel S.p.A., Italy's electric company, with "smart" electric meters that can communicate with the utility. Homes are given a limit on how much wattage they can draw at any moment. The utility programs the meter with that limit, and if the home exceeds it, the meter pulls the plug. To prevent blackouts, the Aristons work together to stay below Enel's radar, giving priority to certain appliances at certain times.

But power pinching has proved just a foot in the door. With the Aristons in place, there's no limit on the services Merloni or others can offer. Ones already in place include monitoring: If the dishwasher springs a leak, it can sound an alarm and call the owner's cell phone; if the refrigerator is working too hard to keep cool, it can tell Merloni, which can suggest a service call.

Merloni also sells a Web pad that lets consumers download recipes for particular dishes to the oven. And it's marketing pay-per-use clothes washers: Merloni owns the washer; when someone does a load of laundry the washer alerts Merloni, which charges the consumer's account.

In 2001 Merloni sold 1 million refrigerators alone. The lesson is clear: Once someone creates a need for connected appliances, it shouldn't be long before your customers start asking for them.

1. The homeowner downloads a recipe from the appliance company's Web site. 2. The company sends the recipe's oven settings via the phone line to the tele-link, which forwards it via the power lines to the oven, which stores it in memory. 3. When it's time to begin cooking, the homeowner chooses that recipe from the oven's menu screen.

1. The smart electric meter warns the appliances when they are using too much power. 2. To reduce consumption, the appliances take turns drawing power, basing priority on what each is doing at the time. 3. A data concentater (1 per 100 homes) connects the meter to the utility using the cellular network.

1. The dishwasher springs a leak. It sounds an audible alarm and sends a warning via the power lines to the tele-link, which forwards it to the appliance company's Web site. 2. The appliance company calls the homeowner's cell phone.