One issue here is that there are far more code contributions (and snippets - which I think can also benefit from categorization) than there are tutorials, faqlets and categorized questions:
I also think this is a useful way of aiding research, but I wonder how efficient it would be to maintain a categorization of such a large pool of nodes, both in terms of database load (is nodegroup
the right construct for this?) and for the users that would have to maintain the categories.
curators++ (I work with real curators - they are a delightful bunch!)