What should I type in the search box,if I want to exclude all results from a particular website?
The search script doesn't do that as is. One way you could do it would be to change it slightly to repurpose the uq variable. Change
and Url matches $$suq
to
and Url not matches $$suq
Then provide an extra box on the search form to enter urls to exclude such as http://www.someplace.com%