is be I didn't say we should implement a category scheme purely by code. I can think of several better methods to providing the utility of categories than inserting hidden metadata tags. I should have more time in the coming weeks to make some explicit suggestions--that is, mock up examples, etc. I think that having a categorization project (a la dmoz for Wikipedia) would be a fine idea, as long as the work, and the data, are separate from the root Wikipedia. In fact, the best thing would be to work on developing ways for outside projects to hook easily into the Wikipedia content without having to be a Bomis-hosted project, prolly by having an XML hook. If we did so, I could imagine a group at the MIT Media Lab or the Cyc project figuring out some bad-ass way of navigating Wikipedia content, etc. Adding hidden content is unwiki. What I'd like to see is an explicit wiki-statement of what is the desired functionality--that is, what is the utility missing--that a category scheme would provide. Then we can discuss particular implementations separately--for example, is it better to use a system which has a single ontology or a system which allows for dynamic ontologies?