I think every tag should have an user attached to it implicitly. That is tagging a post with a certain tag should also make it appear in #tag.username of the tagging user. But the personal tag doesn't appear in the tag list unless it was explicitly set. Imagine oscar is a top contributor, posting interesting articles on all sorts of subject, but also a fan of an underwater pan flute group of which he posts videos day in and day out under the tag #music. In this condition following oscar would mean a sizable portion of my feed is now underwater pan flute. But I don't want to filter #music because I actually like music that's not underwater pan flute. If all tag are implicitly attached to the user I could follow oscar and filter #music.oscar without oscar having to used one off this 2 tags as #music@ I don't know if that would work for the matter at hand but it would be very helpful to combine tags & user when following or filtering.