It is the first place to go to for answers to 'how do I' or 'how does this work' kind of questions which, as a development team, we ask a lot. As questions arise we strive to record them, so that Stack Overflow for Teams can answer the question next time it comes around. It's nicely easy to signup new users.
Stack Overflow for teams serves as a great repository of knowledge for our teams. As well as asking questions for others to answer, we often write and answer questions ourselves in order to preserve a process or piece of information for future use by ourselves or others within the team.
The fact I can use this exactly how I would use stack overflow is perfect for our organisation, it's easy to search through and find exactly what I need relevant to our organisation.