I noticed that on Facebook, chat and private messages are synched. So if you talk to someone on the chat, the conversation can also be viewed in the private message view and vice versa. I think this is a great feature as it unites the different channels to communicate and also works great as a chronicle of all your conversations on the site.
I wondered if this could be done with ArrowChat as well? Taking Buddypress as an example, Arrowchat could write a private message for every message that is sent through it, or, better yet, fully work on the private message tables.
I figure this would be an integration specific thing, since every CMS has a different infrastructure for private messages and some don't have those at all. So maybe this could (or should) be realized as a modification?