There is also https://github.com/ether/etherpad-lite

I wish GitHub used something like that to edit its wikis. Telling me somebody else saved a new version of the doc I'm working on is so uncool.

Pro tip: git clone the wiki and work on it locally. Easier to merge as well

I know, but it's hard to resist editing the document in the web page while talking about it with a remote coworker. No commit, no push, only save. Then I discover he made another edit to the page :-(

I liked much more the workflow when a customer decided to use Google Docs for the technical documentation. We were editing and checking documents live with multiple cursors in the same screen.

Absolutely—they should integrate this kind of workflow into the web UX :D

Oh nice! I didn't realize Hackpad's code got opensource after Dropbox shut it down.

I really† liked Hackpad as a wiki for my team; it was a lot easier to jot down thoughts and better followed the spirit of a wiki (from "quick" in Hawaiian), than the so-called "wikis" we see nowadays that are just bad CMS tools... I'm looking at you, Confluence.

†: enough to be a paying customer.

This is a fork of the Dropbox code as the original is not maintained by them anymore.