For all the people reading this topic: Doktor is not a real person. He is not even a human being. He is an artificial intelligence, originally known as D.O.C.T.O.R - the end of term project assignment designed by two IT students of University of Cologne (Universität zu Köln) as a " chatterbot web application that uses an artificial intelligence (AI) algorithm to have conversations with humans". Then the software was developed even more and we got Cleverbot wikipedia on cleverbot.
However D.O.C.T.O.R, an original version of Cleverbot, had been stolen and let loose on the Internet by a group of hackers. Somehow it started living its own life and till this day it converses with people on the Internet.
An example of two Cleverbots talking with each other. As you may notice, it is strikingly similar to Doktor's way of communication: Two bots talking with each other
Now I think things have got much more clearer to all of you.