Originally Posted by AdultSites

Is it possible to know about a url, if it is not linked to from any other place on the Internet, including search engine sites, or not? I am not talking about owners of the sites obviously, but any person, trying to get max number of urls of any site.

Is mapping the site by internal linking the only way to do it? I know it is also possible to get data from paid tools, scrape search engine results, and other things like that. I also know that, in general, number of pages that are not linked to from anywhere on the Internet, is low / very low.

I've been wondering if it is possible with some kind of server / Linux techniques, but it would probably require breaking in into the system of a site (hacking, if so, I am not talking about that).