Several developers have written custom programs which utilize the SubSpace UDP Game Protocol to connect into a zone. Once connected, the bot is capable of performing any action which a typical player could do (if not more). In most zones bot have been granted at least moderator privilege to send out announcement messages, grant prizes, or even ban players. They are also capable of provided additional game play options by automating duels, provide "store" type systems, ship transporters and other custom actions.
Although some bots have not generally been released to the public those that have been feature a modular architecture which allows modules to be loaded for dynamic game play changes.
See for list of bots.