Well, that ended in a rather fantastical manner. All's well that ends in Robin Williams I suppose, but I know that's just not true. Sometimes, I get a little cute with my metaphors. What I was trying to relay was that a single piece of information is often loaded with much more than appears. Sometimes that additional information is structured, and sometimes it's not. For instance, knowing my name, James, you also know that I occasionally babble on this blog. Those of you that know me personally, and I assume that is all of you as this isn't worthy of much anonymous acclaim, also recall much more by just its mention. You know my full name, my job, my other friends, some of you my parentage. My position at my work is part of a hierarchy. As is my lineage. Those structures aren't obsolete, they're just to be used in more specific situations. Overall, all of this information, is a nice sticky conglomerate of data. And that's where it adds value to tagging. Just James gets you all that other information as well, if it can be associated in some form of metatagging. Thus endeth the poor rambling.
CLARIFICATION - I see it kind of like algebraic substitution with a large number of known items. We have an item x. We know x = y + z. We know y = w + 1. We know z = 2 * v. Via substitution our original item x becomes:
x = y + z
x = (w+1) + (2 * v)
Just x has given us a good deal more because we know those other relationships. They're built into it.