SmartMedia
Physically smaller than a book of matches and about as thick as a credit card. SmartMedia (SM) cards have no controller, they are simply memory that has been laminated on a plastic card. The controller has to be built into the camera and this causes incompatibilities with cameras made before 2001 and the new, higher capacity 64MB and 128MB size cards.
Before you buy a 64MB or 128MB card for your pre-2001 camera, check to see if your camera can accomodate it.
It's now 2003 and SmartMedia cards -still- top out at 128MB. Where are the bigger SM cards? Nobody has come right out and said it but, SmartMedia memory is pretty much dead in the water at 128MB and we do -not- expect to see any further capacity increase.