firstly the DS came out with it's big frame and stuff and touch screen, then more colours came out for it
then the Ds lite came featuring a bigger and brighter screen and smaller frame and again more colours came out
and the DSi came out with dsiware like the wii only for ds and the internet was free instead of 20$ for regular ds/ lite again then more colours came out
now the dsi XL is out with a 93% larger screen then the ds lite and bigger everything also it comes with brain age dsiware for free
right now in JapanNintendo is attempting to make a 3ds that has 3d capabilities without the glasses