Super G was a proprietary protocol created by Atheros that used channel bonding in order to give 802.11G twice the range and twice the speed (although not at the same time). The 2x speed part only worked if you had a card based on the Atheros chipset as well as a router based on the same chipset.

I had a card and a router based on that chipset about 5 years ago. It was great, I easily got 2-3x the range of standard 802.11g at that time. The speed fluctuated wildly but that wasn't really too much of a problem. It easily beat out every other router I owned until my current Cisco that is based on the final 802.11n spec. However, it did not play nicely with Broadcom chipsets of that era and absolutely despised Intel based cards of that era as well.