Seach Not and Find the Answer
Let me explain, as Doug Kaye uses in his quest to find what is wrong with searching, a person six months or more ago could have been writing about IT as the possible wave of the future. More recently the same person could have been writing about Ginger. This past week the writer would have started writing about Segway. All were the Dean Kamen invention, but a user searching for a the breadth of our writing on Segway could easily miss our mention of IT or Ginger. The user would have to know to search on these other terms, if they did not they may not find our work. We loose.
This is where metadata helps out. If the information is tagged with a term that classifies this information or could have synonymous relationships established from that metadata item (personal powered transportation = IT, Ginger, Segway...) would greatly help the search. Most of us have been worked on projects that have had searches yet we constantly had users asking us were our information on "xyz" could be found, as they did not find it in the search and they know they read it on our site. That is a large persistent problem. Searching is not a solution only a patch that leaks.
By the way taxonomies can be fluid, they have to be as usage changes.