I am interested in writing a twenty questions algorithm similar to what akinator and, to a lesser extent, 20q.net uses. The latter seems to focus more on objects, explicitly telling you not to think of persons or places. One could say that akinator is more general, allowing you to think of literally anything, including abstractions such as "my brother".
The problem with this is that I don't know what algorithm these sites use, but from what I read they seem to be using a probabilistic approach in which questions are given a certain fitness based on how many times they have to lead to correct guesses. This SO question presents several techniques, but rather vaguely, and I would be interested in more details.
So, what could be an accurate and efficient algorithm for playing twenty questions?
I am interested in details regarding:
What question to ask next.
How to make the best guess at the end of the 20 questions.
How to insert a new object and a new question into the database.
How to query (1, 2) and update (3) the database efficiently.
I realize this may not be easy and I'm not asking for code or a 2000 words presentation. Just a few sentences about each operation and the underlying data structures should be enough to get me started.