The main intent of the search is to retrieve a list of urls that the site crawled for a given subdomain, domain or tld. So for now you can do that using reversed url notation. Which I admit is not very intuitive.
We're toying with the idea of implementing some sort of wild card that way we can present the urls in natural order. Something like *.google.com to retrieve all urls under google. But we wanted to judge the level of interest first. After all "done" is better than "perfect".