Functional categories simply describe the overall type of a page: is it
- Category:Page Type
- Category:Technology - Describe a technology and how to apply it
- Category:Best Practice - Describe the best way of doing a common task (like, say, digging a latrine)
- Category:Decision Support - Describe the differences between options and help a reader choose between them ("which CF bulb is best for me?", "how should I spend my home energy efficiency renovation dollar?")
- Category:Project Homepage - The home page of a project hosted here
- Category:Open Question - see Provisional Research Workflow
- Category:Answered Question - see Provisional Research Workflow
I would expect a lot more page types to arise.