expand_less Wiki blew my mind, it has been one of several formative experiences toward better understandings of the web and hypertext and the Internet, and community.
 
Wiki is blogging's older, slower, less linear, more influential step-cousin.http://en.wikipedia.org/wiki/Wiki
 
The original - Ward's Wiki, host to early development of [[programming]] [[patterns]].
http://open.wikiblogplanet.com/http://www.wikipatterns.com/
 
Personal public wikis of note:
http://webseitz.fluxent.com/wiki/
http://webbrain.com/brainpage/brain/3D80058C-14D8-5361-0B61-A061F89BAF87