Hi, I'm DexDor (Dex for short) - (amongst other things) a male Wikipedia editor.
In Wikipedia I mainly
wikignome - in particular to improve categorization of articles and making related changes (e.g. fixing
WP:REFERS, splitting articles that are on more than one subject, adding links to Wiktionary/Commons etc).
Category intersection can be used to detect categories that are at an anomalous position in the category structure - e.g. below both
Category:Articles and
Category:Help (a page can't be both encyclopedic content and a help page so there should be no categories for such pages). I chose 12 high level categories (Articles, Books, Dabs, Essays, Files, Help, Inactive pages, Portals, Redirects, Templates, Users and WikiProjects) - those categories with a letter in brackets shown in the diagram below.
Other combinations of Articles and another high level category for pages for readers - AB. E.g.
Category:Wikipedia books on the United Kingdom. One problem here is that a "Wikipedia books on foo" category can include pages in User namespace which is an exception to the normal rule that user pages are not categorized as articles - that exception could make it more difficult to detect incorrectly categorized user pages. One solution would be to create categories such as "Category:Wikipedia community books on the United Kingdom" (see
Category:Wikipedia books (community books)) and not allow other book categories to be in article categories - however, this would be a significant change from existing categorization. Another solution would be to have a rule that only community books (i.e. in Wikipedia namespace) can be placed in topic-based books categories - e.g. in
Help:Books#Saving_and_sharing_your_book_with_others (which really needs to say something about categorization).
Other combinations of Articles and another high level category - AD, AF, AH, AP, AT, AW.
The remainder are FI,HE, HF, IP, IT, IU, IW, PF, TF, TH, UH, WH, TP, WP, UT, FW - these need further analysis/discussion/cleanup.
I'm also using category intersection to detect individual pages that are mis-categorized (e.g. talk pages under
Category:Articles), but it many cases it's necessary to sort out anomalies in the category structure first.