Eliza is a Chatterbot that was originaly written by Joseph Waizenbaum back in 1966.
Originaly the program was created to portrayed a rogerian therapist and
trough the first conversations with Eliza, people thought that she was a
real person (psychatrist) however Eliza was and is still is a program that
use pattern matching and sentence transposition in order to respond to
the user that she is speaking to. Even thow the first Eliza Chatterbot was quiet
simplistic
in the ways it handles a conversation, there are still many improvements
that we could add to make the program behave more intelligently. One of
these interesting features would be the capacity for the program to learn
new keywords during a conversation so that it can continuously extend it's
database. For more details about how to create your own Eliza or simply your
own chatbot, you can consult the Chatbot Tutorial available on these website.