What is the Deep Web?
Basically, the deep web is the unindexed and hidden part of the internet. This includes sites that have no search engines, and are otherwise invisible to the average user. This includes things like wikis, social media and email accounts.
The deep web also includes fee-for-service websites, such as Netflix, that require customers to pay a small fee for access to their content. These sites are a big source of the deep web.