[Izzy]

From asking 20 questions it can effectively eliminate over 1 million possibilities or 2^20. If you take away the probability factor and just look at it as yes or no questions than it is cutting the possible results in half after each question, or as close as it can. Once it cuts the results in half 20 times over it returns the result with the highest popularity.

But it is actually way more complicated than that and I'm not entirely sure how it works other than that.