Last night I was thinking about simple concepts we use everyday to communicate. I'm very unpleased to not have a fitting example, but I think I'll be able to let you understand.
Sometimes happens to tell someone: «Have you watched Star Trek?» and our mate will answer: «Do you mean the movie or the tv show?» This is a very silly example but sometimes things need to be qualified to be exact.
OK, let's go back to Tagsistant and your full episode collection of star trek tv shows and movies and video games and whatever. It would be very nice to have category tagging in Tagsistant to tell that the first are "tvshow:startrek", the second are "movie:startrek" and the third are "videogames:startrek".
So we'll be able to find everything about Star Trek with an usual
$ ls tags/startrek/
query, but we'll also find all Star Trek tv shows by
$ ls tags/tvshow:startrek/
and also all our tv shows by searching for
$ ls tags/tvshow:/
(note the colon at the end).