Votebots are definitely not permitted. The Chatterbox FAQ says that bots that talk on the CB are not tolerated at all, but a bot can read the CB. I have not read a rule on whether posting by a bot is allowed or not. There's a rule about multiple user accounts used by the same person. Bots should naturally follow etiquette like not putting too much load on the servers, and not sending private messages to someone who doesn't request it.

In other cases, apply common sense, or ask permission from the gods to stay on the safe side.

Btw, the XML tickers might help you if you write a bot.