Looks like a great tool. "YAPTA" continues tracking prices on a flight after
you purchase it, so you can qualify for a refund even on a restricted
ticket if it drops." There is a little-known rule in the airline industry
called the "guaranteed airfare rule." If you buy a ticket directly from an
airline and the price later drops, you are eligible for a refund. http://blogs.business2.com/business2blog/2007/04/startup_watch_y.html
