TiddlyWiki as note system

TiddlyWiki is a wiki (sort of) that also happens to be completely self-contained in one HTML file…including being able to edit and save the contents back to disk. It does this through some JavaScript magic, but basically it allows me to have a local copy on my hard drive which I can “run” in my browser. Since it’s one file, it could also be copied to a (for example) USB keychain and carried around and run anywhere, on any OS that gives you access to a supported browser, which today means anything that can run Firefox or IE.