What is a deep web?
The deep site is a part of the Internet that is outside the standard search method. The standard search engine will find a website by calling one page and clicking all links. This allows them to improve from one page like a giant web and search for a page behind the page through the connection. This process only captures a fraction of the pages that exist on the Internet; A huge amount of data is completely not included for one of the many reasons. This site will never appear in a standard search engine and are therefore invisible to most site users.
The surface site is part of the Internet with which most users are known. This part contains standard websites and web services that most users know about. The deep site consists of information that only specific parts of Internet users are aware of or have access. The deep site is huge compared to the surface site; In 2000 it was almost 50 times larger than the surface site.
Reasons for this webMainly because of search engines. As search engines look at links, they cannot access certain types of websites. This site will never enter the system and are therefore never indexed. When a user searches for one of this site, it will never find it because the search engine does not record its existence or its access to it.
There are a number of different types of pages that are difficult or impossible for the search engine. Dynamic and database websites are virtually impossible because they require a specific input. These websites are created on site, often via user input. Since the dynamic page does not exist until it is needed, the search engine will skip them because they do not know what to apply.
private or defended websites forms another large part of the deep site. Because this site requires login data ORImmandering data and search machine are not even blocked in accessing the information on the other side of the login. Even with this problem, some sites based on login are part of the surface site. The site sets a special provision that allows engines to search your site. This is common for pages that have open registration and want to generate further traffic.
Another large part of the deep site is made of unconnected or limited websites. These sites have no links to external resources or actively block existing links. This prevents search engines from hitting the page, so it never adds to any lists. This used to be common among personal websites, but changes in the modern use of the website have caused most of the personal pages of connected and indexed.