Wikipedia user Lupin has created a very cool JavaScript-based tool for MediaWiki called Navigation popups. It should work on any MediaWiki installation which allows users to configure their own JavaScripts (this, in itself, is a fairly cool feature that few other wiki engines have). Lupin’s navigation popups show you the first sentences of any Wikipedia article when you hover the mouse over links for a while. The script can operate without causing too much server strain because it only has to get the raw, unparsed wiki text of the pages it previews from the database. All rendering is done on the client side.

Besides giving a nice preview of articles, it gives immediate access to certain functions (such as edit, move, search, discuss, delete ..). It also has some built-in helpers for fixing links that point to disambiguation pages or redirects (these are Wikipedia-typical problems and not necessarily of interest for other wikis).

You can configure it in various ways; for example, you can define after how many seconds the little “popup” (not really a popup since it does not create an actual browser window) appears. Possible future coolness include support for getting pages from other wikis and cascading popups.

I think similar navigation popup functionality should be added to other wiki engines. That’s why this post is in the “Mindshare” category, a new category for cool implementations that are not widely known. Why not help identify and collect cool [[edit:Wikis|wiki ideas]] in the ID wiki itself?