- http://www.scp-wiki.net/ — platform for artistic expression
- http://duolingo.wikia.com/wiki/Duolingo_Wiki — practical FAQ for users, by users (I learned from it quite a few things I needed about the app)
- https://wiki.archlinux.org/ — super practical, ultimate guide/HOWTO for many Linux-related technologies
- https://en.wikipedia.org/wiki/WoWWiki
- not to mention cr*ploads of "corporate wikis" in corporate intranets where any and all information can be lost (ummm... "found" according to official corpo-speak...)
I pose that wiki as a technology is now firmly entrenched and was without doubt revolutionary. (Btw, it was pioneered on http://c2.com, not "Wikipedia itself".)