But they soon began noticing that their high-speed Internet access had become as slow as rush-hour traffic on the 405 freeway.
"I didn't know whether to blame it on the Santa Ana winds or what," recalled Christine Brodeur, the chief executive of Socket Media, a marketing and public relations agency.
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The "what" turned out to be neighbors who had tapped into their system. The additional online traffic nearly choked out the Brodeurs, who pay a $40 monthly fee for their Internet service, slowing their access until it was practically unusable.
Piggybacking, the usually unauthorized tapping into someone else's wireless Internet connection, is no longer the exclusive domain of pilfering computer geeks or shady hackers cruising for unguarded networks. Ordinarily upstanding people are tapping in. As they do, new sets of Internet behaviors are creeping into America's popular culture.
"I don't think it's stealing," said Edwin Caroso, a 21-year-old student at Miami Dade College, echoing an often-heard sentiment.
"I always find people out there who aren't protecting their connection, so I just feel free to go ahead and use it," Caroso said. He added that he tapped into a stranger's network mainly for Web surfing, keeping up with e-mail, text chatting with friends in foreign countries and doing homework.
Many who piggyback say the practice does not feel like theft because it does not seem to take anything away from anyone. One occasional piggybacker recently compared it to "reading the newspaper over someone's shoulder."
Piggybacking, makers of wireless routers say, is increasingly an issue for people who live in densely populated areas like New York City or Chicago, or for anyone clustered in apartment buildings in which Wi-Fi radio waves, with an average range of about 200 feet, can easily bleed through walls, floors and ceilings. Large hotels that offer the service have become bubbling brooks of free access that spill out into nearby homes and restaurants.
"Wi-Fi is in the air, and it is a very low curb, if you will, to step up and use it," said Mike Wolf of ABI Research, a high-technology market research company in Oyster Bay, N.Y.
This is especially true, Wolf said, because so many users do not bother to secure their networks with passwords or encryption programs. The programs are usually shipped with customers' wireless routers, devices that plug into an Internet connection and make access to it wireless. Many home network owners admit that they are oblivious to piggybackers.
Some, like Marla Edwards, who think they have locked intruders out of their networks, learn otherwise. Edwards, a junior at Baruch College in New York, said her husband recently discovered that their home network was not secure after a visiting friend with a laptop easily hopped on.
"There's no gauge, no measuring device that says 48 people are using your access," Edwards said.
When Wolf turns on his computer in his suburban Seattle home, he regularly sees on his screen a list of two or three wireless networks that do not belong to him but are nonetheless available for use. Wolf uses his own wired network at home, but he says he has piggybacked onto someone else's wireless network when traveling.
"On a family vacation this summer we needed to get access," Wolf recalled, explaining that his father, who took along his laptop, needed to send an e-mail message to his boss on the East Coast from Ocean Shores, Wash.. "I said, 'OK, let's drive around the beach with the window open.' We found a signal, and the owner of the network was none the wiser," Wolf said. "It took about five minutes."
Jonathan Bettino, a senior product marketing manager for Belkin, a major maker of wireless network routers based in Compton, Calif., said home-based wireless networks were becoming a way of life. Unless locking out unauthorized users becomes commonplace, piggybacking is likely to increase, too.
Last year, Bettino said, there were more than 44 million broadband networks among the more than 100 million households in the United States. Of that number, 16.2 million are expected to be wireless by the end of this year. In 2003, 3.9 million households had wireless access to the Internet, he said.
Humphrey Cheung, the editor of a technology Web site, Tomshardware.com, measured how plentiful open wireless networks have become. In April 2004, he and some colleagues flew two single-engine airplanes over metropolitan Los Angeles with two wireless laptops.
The project logged more than 4,500 wireless networks, with only about 30 percent of them encrypted to lock out outsiders, Cheung said.
"Most people just plug the thing in," he said of those who buy wireless routers. "Ninety percent of the time it works. You stop at that point and don't bother to turn on its security."