We, and a lot of other people, use HipChat to stay up to date with how everything in our site and third party services are running.

It would be super handy if Xero could send messages to a room in HipChat for certain events like invoice created / paid etc.

Here's an example of someone else heavily integrating their external systems with hipchat to stay up to date across everything: http://blog.hipchat.com/2014/01/07/see-how-artifakt-goes-beyond-chat-with-hipchat-integrations/