Yahoo already uses Bing.
http://duckduckgo.com/?q=hn+Marissa+Mayer+Googifies+Yahoo
http://duckduckgo.com/?q=copperhead+road+lyrics
http://duckduckgo.com/?q=code+perl+%3D~
The top zero click result is from other sources on the web (disclosure the last one comes from my site).
The only search engine I have found which gets close to this is VerticalSet although with the new Bing pricing I am not sure how long it will exist for now.
Yahoo! had a great search engine to begin with. There wasn't anything wrong with it, really. I think Yahoo! just got a bit carried away with the UI aspect of it.
DDG prides itself on privacy and no tracking while giving good results. I don't think Yahoo! would be interested in keeping that tradition.
Though, I could be wrong, of course.
edit: was supposed to reply to the other guy... oops.. message still stands.
That just gets farmed out to google ;)
The Internet has become too big for a Table of Contents to make any sense anymore.
There is a reason why directories died and search took their place. Directories, in the form we know them, do not scale. There are far more people who would work to fill them with junk than there are people who would work to create order from chaos.
And then there's the question of how you remain objective.
And isn't Wikipedia really the answer to what you want? If you want a directory of ... well, not the Internet, but at least of our knowledge? It may not primarily be a link farm, but it usually provides a good starting point for most topics.
It is right here: http://www.dmoz.org/ and unfortunately it is a ghetto.
Wikipedia might not work as a direct replacement for directory services, but when it comes to helping you acquire knowledge, I think it does a better job. Even when the articles you find are sparse because they might help you formulate better queries to stuff into The Google.