Generally, it is very informal and typos, misspellings and abbreviations are tolerated and even encouraged in order to help speed up the process.
Instant messaging can be useful in our offices in many different ways.
Often, you need to ask a quick question and you know the person is available - instant messaging is just the ticket. It can help save on phone charges and time, it can also be used for small group discussions, like picking a date or time for a meeting. Be careful how you use instant messages. If you abuse this communication method, the person at the other end can block your messages. If you are interested in experimenting with innovative stuff, this is something you may want to explore on your own.