One of the common uses of Custom Search Engines is to provide site search. A number of users have suggested that we can improve Custom Search for this application by also including supplemental results in Custom Search Engine's results. We put fewer constraints on what pages go into our supplemental index and therefore there are many pages which are available only there. This is our first step to give you more results. If your search engine operates as a filter and has three sites or less or your search engine includes the whole web, you'll get supplemental results as well. For example, take a look at the Hanayama Puzzle Store search engine I've created. Hanayama makes some great puzzles, but they aren't always so easy to find. The queries "hanayama baroq" (possibly my favorite puzzle of all time) and "hanayama laby" only return supplemental results in this search engine. Check out the FAQ entry about supplemental results for more information.