I am a big fan of the public Stack Overflow version, and now I am glad we'll have a private version for our company. It helps reduce the necessity to answer the same questions over and over, making it much easier for new employees to get answers to common questions.

Instead of going to a person and asking for the solution to a particular issue, we post it on Stack Overflow and the respective person provides the solution. This saves time of both people also if someone else triggers that same issue they quickly find it on stack overflow.

Being able to concise things to a certain topic of business, that is relevant for everyone who can see it