Harald Blåtand who reigned from 940 to 985 was credited for unifying Denmark, bringing order to the country.  Blåtand roughly translated to English means "Bluetooth." But rather than referring to the color of his teeth, Blåtand actually referred to the color of Harald's hair, which was a very dark color that was not typical of Vikings.

Since the development of Bluetooth in 1994 by Swedish telecommunications firm Ericsson, there have been more than 1800 companies worldwide who have signed as members of the Bluetooth Special Interest Group (SIG) in order to build products to the wireless specification, as well as to promote the new technology in the marketplace.

Source: http://www.bellaonline.com/articles/art24461.asp