What is the Visible Web versus the Invisible Web?
The “visible web” is what you see in the results pages from general web search engines such as Google, and Yahoo! or Teoma, and AlltheWeb. The “Invisible web” is what you cannot retrieve in the search results. The “invisible” or “Deep” web pages cannot be “crawled” nor automatically indexed by traditional search engines, primarily because they are protected links inaccessible from the outside. These pages may also link to “searchable databases” on particular web sites that can only be “dynamically generated” when queried from within the site. The traditional search engine cannot do deep searches in these databases. However, you can search them manually if you know where to look.
