How would you implement a category structure like dmoz.org

I don't have a problem with building the category structure. I have a problem trying to figure out how they included similar or other categories similar to a given one. For example, if you choose the "computers / software" category you will see a category for consumer information, games, sports, home etc. These categories don't belong directly under th开发者_Python百科e software category, yet they are similar.

How would you implement something like this?

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From the FAQ page on DMOZ (http://www.dmoz.org/help/geninfo.html#search) :

The ODP is a Web directory, not a search engine. Although we offer a search query, the purpose of the ODP is to list and categorize web sites.

According to their FAQ their content is managed by the user base, and I'd take that to include all aspects of their content and its relationships, much like Wikipedia.

That said, I don't think they're creating relationships between content categories that is served dynamically. I think they are running a Content Management System and the category relationships are simply part of the content.