[wp-hackers] Category Operation (Adjacency vs. Modified Preorder)

[Christopher Johnson]

Had anyone ever considered using a modified pre-order tree to store the post 
categories in? I realize it would mean rewriting several large swaths of 
code in addition to a tool to convert adjacency<->tree.

With all the posts and plugins I've seen relating to filtering and/or 
excluding posts by category ... it would seem that a modifed preorder tree 
would not only simpify queries but would be more "read" efficient. Had this 
ever come up?