When did bluetooth become popular?
The Bluetooth became popular in 2007.* Not too sure?!
There are several different types of keyboards. The current corded types include PS/2 and USB, with USB being the preferred type. As far as cordless keyboards are concerned there are both wireless and Bluetooth models available. Bluetooth models are popular with Apple products, while wireless is popular with PC products.
Bluetooth is a wireless technology. Bluetooth Stereo basically means Wireless technology + Stereo = wireless stereo. :) Some Bluetooth headsets have stereo capability meaning that you can play music on your phone / mp3 player, etc (the device must have bluetooth) and you can use a bluetooth stereo headset to listen to the music from your phone,etc.