How does this work?

[yorkshiregoth]

http://www.quizyourprofile.com/guessyournumber.swf

 

[col]

It got my number right,curious.

 

[Elmer Fudd]

It's all down to the magic of the number nine

 

[Rhythm Thief]

They could miss out all the stages except "Click on the colour that is the same as the number you've chosen." All that crystal ball and door stuff is just a diversionary tactic.
There are five numbers of each colour and five little houses. Each house contains one number of each colour. So, when you click what colour your number is and what house it's in, the answer is given. Simple.