Bluetooth is a short-range wireless technology used to create PANs (Personal Area Networks) among your devices, and with other nearby devices.
Bluetooth allows you to leave your phone in your pocket, while talking on your phone with a Bluetooth headset - with no wires. You can also exchange contact or scheduling information with other Bluetooth-enabled phones nearby, or send such information to a nearby Bluetooth-enabled printer.
Another common use is to give your laptop computer or PDA wireless high-speed Internet access via Bluetooth and your phone.
Many newer automobiles also have Bluetooth, which can interface with a phone in a pocket, to allow automatic hands-free phone capability.
More innovative uses include playing a game against someone with a similar phone nearby, or using a special Bluetooth pen to send SMS messages by simply writing them on paper.
Bluetooth functionality is divided into separate types of connections known as "profiles". Each of the various scenarios outlined above involve a different profile. Not all Bluetooth devices support all profiles.
For example, most phones support the Headset (HSP) and Handsfree (HFP) profiles, for connecting phones to headsets and car audio systems, respectively. Most phones also support stereo sound via the A2DP and AVRC profiles. But not all phones support the Object Exchange (OBEX) profiles, which let you transfer files (like photos). Other optional profiles support connecting to printers (BPP) and keyboards (HID).
Most Bluetooth phones are "class 2", which means the Bluetooth feature has a range of up to 30 feet. Class 1 phones (which are less common) can have a range of up to 300 feet.
Bluetooth operates at 2.4 GHz, an unlicensed band that is used by several other technologies, including Wi-Fi.
Bluetooth is named for the 10th century Viking king Harald Bluetooth, who united Norway and Denmark.