Couldn't make the big "WELCOME TO FLYBYCHAT" left pane go away, so it felt like there was a lot of screen real state that was left unused.

Also the HN lurker I was chatting with raised a good point: there should be different colors for "You" and "Them", would make it much easier to see the flow of the conversation.

EDIT: Would also be easy to add a horizontal bar, to track the last portion of chat you saw before you switched tabs/removed focus from browser