has anyone got info on 'piggy backing' on google to create a search engine that shows a subset of the google items, where of course the subset doesn't include i

has anyone got info on 'piggy backing' on google to create a search engine that shows a subset of the google items, where of course the subset doesn't include irrelevant advertisements, etc? google would try to stop it, i suspect, but might have difficulty getting help from the courts, since such an alternative engine would be basically a provider of pointers to someone else's content, which is of course what google is.