Vander Wal and Categorizing

Not one day after my posting that tagging is really at least a little bit like categorizing, I discover this blog
in which there is a link to presentation by Thomas Vander Wal himself, in which presentation Thomas says:

People are not so much categorizing, as
providing a means to connect items
(placing hooks) and provide their meaning
in their own understanding.

I guess the first part of this disagrees with my claim that tagging does involve categorizing. Although the phrase “not so much” is a little bit confusing. Maybe they are categorizing a little bit even by Vander Wal’s reckoning?

The second part I must admit I don’t understand. What is it to “connect items” and “place hooks”?  Does it literally mean to say that I can “connect” elephant with subatomic particle? What is the mechanism for this? How does it work? Does an arbitrary connection really lead to “tagging that works”?