max_msg is cool ... but a nice feature would be also a max_age that would indicate the oldest message you would like to see. They would be used in conjunction -- something like:
max_msg = 20
max_age = 120
Would logically be ... show me the last 20 messages as long as they are no older than 2 hours (120 mins). The thought is that you probably want to see the last little bit of history (to get caught up) but maybe not what people said yesterday where the conversation left off.
- Bob