Some way others have to tag packages (instead of questions) : http://debtags.alioth.debian.org/.

Install and look at debtags, tagcoll and tagcolledit packages (man debtags). Read the above link, especially:

• People using libtagcoll to bring the Debtags faceted classification approach to domains different than Debian packages: think browser bookmarks, multimedia repositories, mp3 archives, documentation, launcher menus... the approach has big potential to rock everywhere!

Read also (from the same source): http://debtags.alioth.debian.org/paper-debtags.html.

Will demexp use these tools for its own classification?

[dm] Why? Logic File System and its underlying theory encompasses the proposed Debian approach as far as I have understood it? Why to you think we would need to use the Debian system?

[fdl] Well, I see LFS more as the underlying implementation and (possibly) debtags as a way to interact with the tags (from the classifier point of view). Moreover, they provide software to handle tags, but I do not know yet of any graphical client to LFS. Maybe I should read again your proposal of LFS integration in demexp.