Its a neural net implementation, so yeah pretty complex.
And if you want more accurate responses, go to sign up for an account, dont actually sign up. Go back to the home page by typing the URL(dont click back

) and click Play anonymously next time. This gives you more options.
I get:
Yes , No , Unknown, Irrelevant, Sometimes, Maybe,
Probably, Doubtful, Usually, Depends, Rarely, Partly
I'm trying to figure out the minimum number of guesses it needs to guess a really simple object. I like also that once it can't guess and you tell it what you were thinking of, if you click the name, it tells you what answers it was expecting.
Oh yeah I forgot to say, if you're anonymous it only shows G Rated objects. If you wanna play with teh dirty words, sign up and change the censor level.
Oh and for those people complaining its stupid, thats just what the players have programmed into it, since it relies on your answers to form its database. So really its the people playing who've said that, not the AI. And as it says, the best way to fix that is to play the game again and teach it.