Actually, if you want to be technical, AMD's socket setup is less confusing now, sort of. AM2/AM2+ work together, AM3 works in AM2+/AM3 motherboards, nothing but AM3 works in AM3 boards.
But now we have 775, 1156, and 1366. There's going to be two versions of i7s. 775 just came out with those low power quads a bit ago even though it's basically going to be a dead socket soon. 1366 is making a move to server type stuff, besides the i9. And before it's even released, 1156 is slated to be the new default socket.
It was bad enough when they had P4s on 423. 478, and 775. Now it's just some big cluster-somethingorother.