Ask HN: How is knowledge stored within your company?

I am setting up a new entity and want to make sure that things we learn do not get lost; that we have a central place where "all" knowledge is stored and available to anyone within the company.

What do you use to make sure that knowledge does not get lost and that it is accessible by anyone?

If you use a software or SaaS:

- Which one?

- What makes it great?

- What do you miss?