Deep Web vs Surface Web
Surface web by definition, can be found using normal search engines. Deep Web, by its definition, can not be seen by surface web. The surface web’s search bots are based on popularity of backlinks, by the nature of deep web such backlinks will not be found under normal web conditions. Therefore, if there is such a backlink and the surface web can see it, the search result will likely be buried deep in the result stack.
Surface web is often websites of companies, people, and bloggers. Like uncle Joe who writes about local county history trying to remember what his uncle told him. The common man’s authoritative score is questionable, and there is lots of junk research that is being offered as good. Vetting of sources and citations is very much required and may be difficult.
Deep web will have images of court records, census records, maybe archives of old newspapers. The deep web is largely academic databases and government archives which are highly authoritative. Vetting of sources is much easier and quicker than Surface Web.