I will add to #5, use proper capitalization. I don't know what it is with people who don't capitalize proper nouns. It comes off as diminutive and having a lack of confidence.

One of my favorite productivity tools is also my worst distraction. I love instant messaging tools because it allows collaboration and quick dialogs without meetings and phone calls. However, it is an interruption every time a message is sent and replies are expected immediately. I have begun to ask people to email me any question or request that is not urgent. I have also been asking people to schedule IM chats, even if it is "Can we chat in 10 minutes?" so that I can continue working on the task at hand.