I use vimwiki in combination with Dropbox and some symlinks to keep my text-only wiki portable. Useful for tech snippets and notes when I don't want to fire up a browser...<p>... speaking of which: Some commenters suggest various browser-based wikis. My favourite is the JavaScript-only tiddlywiki:<p><a href="http://tiddlywiki.com/" rel="nofollow">http://tiddlywiki.com/</a><p>It's got bunches of plugins and compatible variants (I use the mGSD variant for GTD), so it's way more than just a wiki.<p>I keep this in my Dropbox too, and can work on it with any browser, Windows or Linux, with or without git or any other HTTP server, online or offline.