Fancy gadgets such as portable cell phone jammer that can be used to jam cell phone signals are illegal and potentially dangerous, experts say.

So, why was Google lighting up Monday with people searching for them? You can thank a guy in Philadelphia who got fed up with folks yakking during his daily bus ride and a local news reporter who happens to ride the same bus.

Days after the story broke on Friday, the apparently fresh interest in the devices, which can be had online for anywhere from less than $40 to more than $1,000, is cause for concern among some security experts.

"The general public doesn't realize what they're jamming if they were to start using these things," said Richard Mislan, an assistant professor of computer and information technology at Purdue University who specializes in cyber forensics. "What are not obvious are all the wireless connectivity systems that are in the background and maintaining data communications in our daily lives."

Last week, Philadelphia TV station NBC10 reported on a man who admitted to using a portable phone jammer during his bus commute to shut down fellow passengers when they were talking loudly.