Well...heres a few examples:
:: A Forum Bot ::
A forum bot is a little program that you install on your webserver. When someone posts, the bot automaticly replys with some weird message.
:: A Chat Bot ::
A chat bot is a bot that replys to you when you instant messenge them. Sometimes they can be funny, other times they can get anoying if not properly coded. If you have AOL Instant Messenger, message the username SmarterChild, and have a chat with him
Nick