App Tracking

Got into an interesting discussion with some friends and just curious what the opinions of the masses are. In a tournament setting is it against the spirit of the game or even illegal if you use a game tracker like vphammer.com which gives you much more in depth stats regarding the state of the game? Is it an unfair advantage to track the likelihood of secondaries coming up for both you and your opponent so you can plan your turns accordingly? Or is this frowned upon/illegal as keeping track of those things is part of the skill of the game?