Have you ever noticed that most popular wireless communications methods use 2.4GHz? This includes Wifi (802.11), BlueTooth, cordless phones, and more? Gizmodo provides a very understandable explanation. Basically, it turns out that the 2.4 GHz band of the RF spectrum was set aside by the FCC for unlicensed communications (this means you don't need an FCC license to run your WiFi Access Point or BlueTooth headset). Furthermore, because all of these systems use frequency-hopping technology (which means the radios check a particular frequency to make sure it is open before transmitting), you can have multiple products running in the same physical area without interference from each other.