footprint on my mind

People in information systems are using the term "footprint" in odd ways.

Just now, listening to NPR, I heard a man describe the 30 mile radius of wireless internet access as a "large foot print."

I'm not sure how much I like calling an effective wireless communications area a "footprint."

People also describe cell phones' dimensions as footprints. Why does everyone differ the use of words such as "size" or "dimensions" in favor of "footprint"?

I guess footprint is the cool new term. I guess I should go into nano-footprint studies so I can collect all the future research money.