What is blue in Bluetooth?

It was a few years before a friend of mine asked me whether I have Bluetooth in my phone. I asked him what kind of tooth it exactly is, because I had no idea what he was asking (I was using my gaudy Nokia 1110i at that time and he laughed on seeing it coming out from my pocket). Forgetting the fact that I have often been lagging behind technologies, let us talk about Bluetooth this time.
I'm sure many of you might have wondered how such a name fell upon a most modern technology. I had many scientific hypotheses of myself on this name before I stumbled upon the fact that Bluetooth got its name from that of a Danish king! Yes really. This name came from that of Harold "Bluetooth" Gormsson, who ruled Denmark in the first century. Actually, Bluetooth was his nickname because of his fondness for blueberries which made his teeth blue. He is considered as one of the most influential kings of Denmark and that was why Ericson, which is a Danish company, named their technology after him. The Bluetooth logo is the initials of Harold Bluetooth in runic alphabet. He was famous for uniting the rebellious tribes of Scandinavia and for bringing them under a single kingdom. If you don't know it, that is exactly what 'our bluetooth' also does- uniting various technologies.
If you are not so bored yet, let me tell you a bit of technology now. You know that bluetooth is an electronic communication technology. When two electronic devices want to communicate with each other, they have to agree on several conditions. First, how to communicate physically. It means, whether to use wires or some wireless signal forms and if they use wires how many wires are required and so on. Even after settling on this, there are many other problems to solve. E.g.,how much data will be sent at a time; the transfer rate which depends on the device used. It means, for an effective communication a set of commands and responses known as Protocol has to be developed. Bluetooth is a protocol developed for this purpose by Ericson in 1994. The Bluetooth technology uses radio frequency waves and takes very low transmission power which saves battery charge (Now you can guess why Bluetooth transfer works only in small distances). It establishes automatic agreement between two electronic devices and so does not require the intervention of user.
[Note: There is an international body called Bluetooth Special Interest Group(SIG) that oversees the development of new Bluetooth standards and new technologies and trademarks.]