How does cleverbot work?

[The Knowing]

To try and put it simply

If you ask clever bot "How is the weather?" It will answer with something random or not reply if it never recorded that sentence. Later, to a random other person, cleaver bot will ask "How is the weather?" to someone else. If someone replies to the question it will get saved...eg. "cloudy", "raining cats and dogs", "nice" etc.

The same works with roleplaying. All you have to do to see how it can reply so well is think of how many people have ever spoke with clever bot. The reply it chooses are ones people most commonly give to it.