the idea in the general: is to continuously grow metadata from the use of the data - keeping a history of use, learning patterns, links, and contexts from that history. eventually establishing a strong semantic layer over the data.
in the specific: a plugin for my personal wiki of choice, WikidPad. The plugin, lets call it WikidPadMonitor for now, when in 'learning mode' should collect information about the wikipages you open, the wikilinks you follow, and the patterns of wiki and tag usage - and use this to grow useable metadata.
Eventually, this emergent metadata could be used to establish a new measure of the strength of the links between wikipages, make predictions about the page being looked for, and discover context..
well, thats the idea, anyhow: growing metadata in the wikigarden.