err is a plugin-based XMPP chatbot designed to be easily deployable, extensible, and maintainable. It is written in Python, and is based on jabberbot and yapsy with some minor modifications to the first one. It has been tested with HipChat and Openfire, but should be compatible with any XMPP/Jabber servers. It can be set up so that a restricted list of persons have administration rights. Dynamic plugin architecture: the bot admin can install/uninstall/enable/disable plugins dynamically just by chatting with the bot. Supports MUCs (chatrooms). Can proxy and route one to one messages to MUC so it can enable simpler XMPP notifiers to be MUC compatible (such as the Jira XMPP notifier). It is easily extensible. It provides an an automatic persistence store per plugin, and a !help command that dynamically generates the documentation from the Python docstrings of the commands. Create a user for the bot on your private XMPP server or a public server like jabber.org. Optionally, you can create a MUC (also called a conference room or chatroom) in which you can interact with the bot.
pidgin privacy please is a pidgin plugin to stop spammers from annoying you. You can block messages from certain users, block messages from people who are not on your contact list, and suppress repeated authorization requests. Optionally, senders of blocked messages can be notified with an auto-reply.
JTelIRC is an advanced IRC framework for Java. It is mainly intended for writing automated clients ("bots"), but may be used for normal clients as well. It provides an intuitive and well documented Java interface to IRC and makes it extremely easy to write advanced clients quickly.