And the question then is, will wikipedia allow us to create all these sub-categories? (linux-audio-Demos, linux-audio-digital-dj, and so on.)
I am not an experienced Wikipedia contributor, but it seems that they are generally fine with it: http://en.wikipedia.org/wiki/Wikipedia:Be_bold "It is usually worth proposing any changes to categories and/or templates on talk or other relevant WikiProject pages prior to making any change." The general guidelines for creating categories and subcategories are here: http://en.wikipedia.org/wiki/Wikipedia:Categorization#How_to_create_categories
I'd say that wikipedia should be used as a summary page, rather than an exhaustive resource with app-specific documentation. So, I guess in that respect I do agree with your ideas. However, I do not see it as an exhaustive documentation resource for every app.
I think that is what the Wikipedia policies also have in mind. I thought that the point, from the subject, was attracting more developers (and non-Linux users, especially). For that purpose, Wikipedia is probably a much better starting point than a more Linux-centric site. As for the specific documentation, my suggestion is to limit the number of wikis. One is really better than three. It means less maintenance work for the maintainers (and thanks to those who decide to do it). It will be much easier for a community of this limited size to clean up the vandalism of spammers or correct mistakes than dividing our efforts among three locations. Maybe most importantly, if I have a question, I don't have to go to three different places to look for the information. Similarly, if I have documentation to contribute, I don't have to go three places to add it. -- Renick Bell http://www.the3rd2nd.com