Martin Sauter has a nice post over at WirelessMoves titled The G Is Dead, Long Live the G!. In the post he discusses how "G" is being misused to death. Here's a quote from Martin:
In almost every report the acronym "4G" is used for just about everything that is faster than a crawling few kbit/s. 4G is HSPA, 4G is LTE, 4G is this, 4G is that. Well, 4G isn't any of it. And quite frankly I am a bit tired and nerved because just like "open" and "free" it has lost any meaning in the mobile world.
2G: Digital technologies that originated as purely circuit-switched ones, later expanded to packet-switched (within the constraints of the old tech)
3G: Both circuit-switched and packet-switched from the ground up
4G: Purely packet-switched