The New York Times' technology columnist, David Pogue, has an interesting proposal for cell phone carriers; employ megabyte rollovers for customers just like they do for minute rollovers.
Fortunately I'm still on the old unlimited plan rather than one of the new tired plans, so I don't usually even pay attention to how much data I consume on my iPhone, but for customers who somehow manage to stay under the cap of whatever plan they are on, this might be a useful option.
