Why do search results vary from engine to engine?
 1. Because different search engines search different
parts of a Web site
2. Because each search engine has its own unique
database of Web pages
3. Because each search engine interprets your search
strategy its own unique way.
Let's try the witchcraft search in MetaCrawler  (http://www.metacrawler.com) and DogPile (http://www.dogpile.com).

It may go by too quickly for you to see, but MetaCrawler does list which engines it's searching as the search is being completed.  The results page ranks the hits (1000 = high relevancy and so on).  The results page also indicates from which search engine the hit was found.  MetaCrawler also provides the annotation from the original search engine.  At the end of every annotation, there is a link back to the original search engines, which can be used if you want to go back to that search engine and see the results for the search you've entered.

Dogpile provides the annotations and ranked hits, but it doesn't indicate from which engine each hit came.