I did a search "Diamond" in Garage Sales. WHen i clicked the first post, it says broken. shouldnt it be that we cannot see that thread anymore?

That topic was created by a spammer and has been deleted. New topics/posts are added to the search engine every 30 minutes, but it takes up to a week for deletions/edits to take effect (due to performance reasons). So by next week you shouldn't be seeing that topic in the search results anymore..