It takes a twist of logic, but I think you can save a lot of search overhead with this approach.

Make the default search depth the first thread in a post, no deeper. Most people doing a search are looking for the answer to their question. The most efficient approach to returning the desired answer is to FIND THE SAME QUESTION. A good thread-starting post lays out the pertinent details right off the bat. This type of post is also the MOST likely to receive good, quality answers.

If you limit the default search depth, maybe then we can get a "Search within Results" option, or at least weight-rated returns?

Thanks for adding in the boolean AND operative, and THANKS for listening to all of the TGO Members (Ads, Ad Placement, Searches, etc). Keep it up!