Wiki is the name for a software that shows you a web page that everyone can edit. There are many different wikis, the most famous one is mediawiki which is used to run wikipedia. tilswiki is yet another wiki software. In contrast to most other wikis it does not require you to click an edit button and then to save your changes - rather it is always in edit mode. So you crank in the text on any tilswiki page and edit it immediately, for example the page you are currently reading.
It uses the contentEditable attribute, andy on Firefox 3 right now.
tilswiki is open source, under the AGPL. Notice the A - source code changes must be shared, even if the modified version is only accessible through a hosted a web app.
An instance of tilswiki is hosted here at http://wiki.tils.net/
Security of tilswiki pages is only based on their URLs (the address you see in the brow
sers address bar). For example, this page has the URL http://wiki.tils.net/about - which is easy to guess an linked from the front page, so it is likely that many people will see it (and can edit it).
http://wiki.tils.net/about