Analyzing freight rail shipments is frequently used to ascertain the trajectory of the economy overall. The New York Times has an article on a company that tracks GPS data from various connected devices and formulates a traffic congestion index.

“People hit the road as they return to work, and businesses ship more freight as their orders increase.” The rise in the index, he said on Friday, “shows the pulse of the economy is starting to beat faster.”

Very interesting use of shared location data.