Finding Cheapest Travel Times

I came across an intriguing App in Bangkok Post's Guru magazine recently named Hopper.
By simply adding in a destination the app is able to indicate high peak and low booking periods.
There is also a predictive element on an analysis if at certain times prices may decrease.
In short order, its like a game of poker, know when to fold, know when to call and when to when to walk away.
Perhaps the best feature is an alert when prices hit lows.