This is one of this topics which importance is underestimated. Keeping centralized collection of documents is common practice which probably has many problems because it's structure in time become a mess, people are not willing to contribute, the technology (and even solutions in projects) is changing so quickly it's impossible to keep documents up to date.
The very important thing here in my opinion is not even tools we are using (although they for sure can help) but developing habits to share knowledge, ask and discuss, update documents when we find out about something
Once I was working with a collegue who has this habit that when he managed to solve a problem, he discribed and show me this. I really appreciate this as I learned a lot from him this way.
Everybody knows that writing documentations from the begining is hard and time consuming. So basically I think we should focus on process of adding content, not only container of the content.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.