Maybe a browse log feature?
This is how I am planning to implement it in my client. Basicly, I have messages between users broken down into conversations. How the conversations start and stop is still kinda up in the air but right now I have it setup to start and stop them when you open and close the window. But basicly I will have it much like in windows explorer where you have a list of conversations on the side, listed by date and you can actualy browse through them or narrow down the list with a search. When you click on a conversation or select several conversations they will come up in the main pain seperated by conversation. From here, you’'ll be able to, print, email, or save it out to a text file, as the raw data is stored in XML.
Maybe thats a little more then what you guys are looking for?