Scenario: A User should be able to Limit his search to :
(A) Google/Or search list Quire results only and not the Entire Web ex: (click here) [ The logic behind is Sentence structured Search, which i believe is more sophisticated than operand search method]
(B) Mentioned Website (independent of the Site tweaked Search box)
(C) User can filter to see only spcefic file format, such as .pdf .doc .zip .exe , and no other results.
(D) The user results from (A) is said as (A1) then the system should be able to use A+A1 or A1 alone or create a new search of either combinations for further steps of search.
Intention: A user has an abstract to complete understanding on a particular concept. the new age search tools are limiting to refine and forced to user to do the job of making the search results meaning full by using tedious complex search quires.
Also read: http://en.wikipedia.org/wiki/Socratic_method
PS: i might be late for this too: http://www.netbase.com/