The food trucks have disrupted the sit-down restaurant business in some cities. I liked this brief post about trucks in downtown LA near the Fashion Institute (FIDM) because it gets in to several aspects of the disruption:

http://blogdowntown.com/2011/01/6013-food-trucks-near-fidm-s...

* The fight over parking spaces (food truck employees "reserving" street parking with their own cars, in advance of a later arrival of the food truck itself)

* Parking tickets as equivalent of rent

* Increases in options and quality

* Disruption of incumbent and lazy chains