Forum software is a more permanent solution than chat based solutions. This is caused by the fact that chat based solutions are chronological in nature, and as the content shifts out of view, it shifts out of working memory.

Forum threads, on the other hand, can be linked and updated. They can have responses and "accepted solutions" when users ask for help. The best thing though, is that they can be shared and suggested to users - allowing other users to help their colleagues indirectly.

Discourse is a fantastic piece of software that allows you to categorize topics, adapt themes to your wants, and provide reports so you know the hot topics.

The Discourse Help Forum, a meta-Discourse implementation.

The Discourse Help Forum, a meta-Discourse implementation.