Note - the reason for switching being the best method is essentially this: you have a probability of 2/3 of being wrong on your first guess. Whenever you are wrong, switching will make you win. So, if you always switch, you will win 2/3 of the time. Much more information with various methods of explanation is available on Wikipedia.
Some interesting statistics:
|Total amount of people who have participated: ||9178|
|Percent who got the car||Percent who got a donkey|
|Those who switched||66%||33%|
|Those who stuck||33%||66%|
|Percent of users who did this|
Some less interesting statistics:
|Door||Percent who picked on first choice||Percent who picked on final||Car was here|
How the experiment is set up
The car is assigned to a random door as you load the first page. Everything is randomised as much as possible. If two doors could be revealed a coin is tossed to decide which one to reveal, the buttons to stick and switch are placed in a random order so users do not choose them because of their placement.
You can email me if you spot a bug or anything else. You can also visit my blog.
Update: it is now on Digg.