TiddlyWiki - a reusable non-linear personal web notebook

TiddlyWiki is published under a BSD OpenSourceLicense that gives you the freedom to use it pretty much however you want, including for commercial purposes, as long as you keep my copyright notice. (You can see the full license text by doing a 'view source' in your browser). If you do use TiddlyWiki I'd appreciate a link back to http://www.tiddlywiki.com.