Tagging could help users in finding the more obscure bits of information. For example, some guy mentions in his blog about an article on a chapter in an American History book that's relevant to Florida during the revolutionary war. Five years later, a search turns up the tag and a student able to snag the book for a report.
What I'm curious about are ways that you could modify searches for tags. Limit searches to published articles or for anything newer than five years? Or linking keywords together to create more precise searches? That would cut down on a lot of the confusion that the article mentions.