Understanding the deep web means you will need to know the levels leading to it. Here is a breife summery Leading to what the Deep web is.
Something to keep in mind about all this is the Internet, and the "World Wide Web" (WWW) are not the same. The Internet is the global system of interconnected computer networks that uses the Internet protocol suite to link devices worldwide. It is a network of networks that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies.
Anything easily access able via you public search engines. Web crawlers have indexed these sites and allow them to be found simply through mainstream search functions (google, Bing, Duckduckgo etc.)
Things from the Deep Web can often be brought up to this level or drop from this level on the Internet-based on SEO, algorithms and the site/server admin discretion.
Deep web content cannot be seen or directly accessed via general search engines. The Deep web is the information stored online that isn't indexed by standard search engines. You don't need any "extra" special tools or a darknet browser to access the deep web; you need to know where to look. Specialised search engines, directories, and wikis can help users locate the data they're looking for. Most Academic networks work on this level.
- Invisible web
- Hidden web
Deep web search engines;
Multi Search engines;
Cluster Analysis Engines;
Speciality Deep Web Engines;
A hidden Web Within the Deep Web