http://www.usatoday.com/travel/news/2006-07-11-southwest-usat_x.htm
When Donald Cloo of Phoenix boarded Southwest Airlines Flight 2444 Monday in San Diego, he did something no passenger had ever done in the 35-year history of the discount carrier. He sat in an assigned seat.
With that, Dallas-based Southwest began an eight-week test with selected flights out of San Diego to see whether assigning seats will speed up the boarding process and allow the carrier to dispatch its planes quicker.