See http://www.nabble.com/User-categories-and-the-fear-of-becoming-a-social-network-td14533705.html for an archive of the mailing list discussion.
The last time I tried to get some additional comments on a user category there was little to no response, so I thought some of you on the mailing list might be able to bring some additional views on this.
I noticed a user pointing to Wikipedia:User categories for discussion/Archive/October 2007#Wikipedians by mental and physiological condition and subcats the other day, and I was a bit surprised to see all of those categories did get deleted. I personally know of a few times such categories were used to help out with article collaboration, and even once during a debate about the handicapped sign being used in templates. In the past I've recommended to people that they were a good way to contact someone who wouldn't be bothered by someone asking questions related to their condition. It's been my assumption that when a user put themselves in such a category (or uses the associated userbox) they were basically listing themselves as a resource, as if to say "I have this condition, and I am inviting any editor that is interested to ask me about it, or ask me about what resources I know of that might help said articles". A lot of Wikipedians have conditions, but don't have an active interest in working on the related articles, but are still willing to help when asked.
It also reminds me of something Wikipedia:WikiProject Anime and manga has done, where it has made a magazine and book listing where users can list what books and magazines they have. So when someone knows that an anime was talked about in a book, they can find who owns the book and ask them for help, or how to cite the information.
While I agree with a great many of these deletion discussions, I think people are not being reasonable in how things can and have been used, or are not considering some of the points I've brought up.
I'm also confused as to why people seem to think that WP:MYSPACE applies to anything that they don't see as helping Wikipedia. Certainly, useless categories should be deleted, but being useless does not mean something is being (or is even practical to be) used for social networking. It also seems to set people off, in that since they are assuming these categories are being used for social networking, reasonable arguments that demonstrate wiki-related use will not be given proper consideration.
Like I said, a lot of these deletions are dead on, but we're also losing a lot of categories that were realistically usable. Should some be taken to DRV? Should a kind of "rationale" page be created to help avoid confusion? Are any of these categories realistically being used for social networking, or are we overreacting? Are babies in lurking in the bath water? Is it bath water in the first place? Green or yellow? Up or down? Paper or plastic?
-- Ned Scott