How do you document what you are learning at work?

Mindmaps, with notes. Allows you to organize the information in a visual hierarchy, so that you can quickly refer back to the notes. I use Freemind[1], an open source tool.

[1] - http://freemind.sourceforge.net/wiki/index.php/Main_Page

If you're using emacs you can use org-mode for note taking. Plus, there are lots of benefits wherein you can organize everything just in plain text.

Some of the previous discussions about org-mode:

https://news.ycombinator.com/item?id=2423276

https://news.ycombinator.com/item?id=8668271

https://news.ycombinator.com/item?id=2091850

From org-mode website: Org mode is for keeping notes, maintaining TODO lists, planning projects, and authoring documents with a fast and effective plain-text system.

http://orgmode.org/

I use OneNote. I have a Notebook for each project I'm on, with tabs to keep my notes organized. My small team, 3 people, has a shared OneNote Notebook to allow collaboration. At my previous employer, we used Atlassian's Confluence.

I have a few text files at work that I keep track of things. I treat it more as a reference file/personal FAQ file, some notes are verbose and some are terse. When I am learning on a side project I keep my notes in Google docs. I take the time to format those notes better so I can study them easily. Google Docs has history and warns you when you delete a file. What do you use versioning for? I correct my notes when I discover they are wrong, and if we release a new version of the product, I just record the new behaviour in addition to the old behaviour (along with dates, build numbers etc)

I'm using tiddlywiki and I must say it's doing an amazing job. It doesn't stand on the way, works via mobile, everything is fine so far. I am slowly transitioning from Evernote. However if someone doesn't pick-it-up it will probably cease[1] by the end of 2016.

[1] http://osmo-service.tiddlyspace.com/ServiceUpdate20160112

Wiki, that way other people can contribute as they learn incrementally.

Wiki gardening is a thing, though, and without it, doom will follow.

At my last job we did the same thing, but I heavily customized the wiki to include endpoint testing, DB access, context-sensitive autocomplete, etc. It was pretty cool.

I found Evernote was the easiest way to always have it around.

A directory of markdown files. I use git for version control.

I just write them to text files and usually lose them.

I use gist.github.com