Interesting story about the new fad in Europe of people that are using Bluetooth technology to send what many may consider to be spam, which can be found here.
Many cell phones outside the U.S. come with Bluetooth built in, and many more of the new cell phones released in the U.S. in 2004 will also have Bluetooth included. Essentially a person who wants to Bluejack someone simply sets their phone to be discoverable and search for Bluetooth phones within your immediate area. Of course, the ability to block this kind of activity is built into Bluetooth devices.
This reminds me of a blend between the beginning of e-mail spam and the continuing problem of people not enabling the security on their home wireless networks.