Thats awesome! Is there a reason its for logged in users only? I think it would be best if it was available to everyone since I see this becoming a good repository for useful information like reddit so having it easier for people to search would be convenient.
I think it would be convenient if it was a search field on the top middle of the page instead of a button that takes us to a search page. It would also be nice if the Title section of the Create Post page automatically searched and displayed a dropdown of different posts\comments with similar text so people can find existing threads\answers they're looking for when making a thread.
As it's a new feature there may be performance issues or other problems to work out so I didn't want to make it too widely available immediately. But I agree it should be usable by non-logged-in people too.