We are using GitLab and with the latest CE it also has GitLab Pages included. Which is like github pages.
I also loved the idea of runbooks, which is also from GitLab <3 Where you collect all valueable information in one place.
So we have one repo which covers infrastructure, smaller howtos, information about staging, deployments, styleguides, coding conventions, etc. in that repo.
For static generation we use GitBook with the FAQ theme. It's it really nice, because of the GitLab CI runner you only need to push your markdown files and it will build it.
However we also have some project related things in Confluence. Which is a bit, clumpy for my taste. It got a hell lot of features, but is kind of slow and... does not feel that good.
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.