This is an old revision of the document!
It is a standard for short range wireless communication between various electronic devices such as keyboard, computer, laptop, PDA, smartphone and many others. 1)
It has a Danish king's name. Harold 'Blåtand' Gormsson, the 10th century King of Denmark, enjoyed blueberries so much that his teeth were blue forever. The “Bluetooth” version of his username is clearly anglicized.