August of last year, Yahoo began pointing "link:" and "linkdomain:" without other search operators queries towards Site Explorer. Today, Yahoo will be redirecting "domain:" and "hostname:" queries to Site Explorer as well. So if you do a search at search.yahoo.com and it is using those query types, they will soon redirect to Site Explorer. It appears that this is not live yet, but Yahoo tells me it will happen today some time.
Yahoo, Site Explorer, Search Query, Search Engine