The search box at the top of the page is Google, the difference is it's restricted to searching this site. How to form the question is the key to success. If you want to know the offset of the rear wheel and say "wheels", following a couple ad lines at the top you'll see a list of all the threads that mentioned wheels, including the vacation to VT where someone bought a wheel of cheese.
If you ask for "wheel offsets' it should pare down the list considerably, and "rear wheel offset" pare it down even more. But keep in mind the key words you search for may be in any post in the listed threads, even if that post is thread drift and not related to what the thread is about.