Deep Web vs. Dark Web

The deep web refers to portions of the internet that are not indexed by standard search engines (also called web crawlers). This includes private databases, emails, many social media networks, content behind paywalls, and membership websites not meant for public viewing. By most estimates, the deep web accounts for 90% of the internet. 

The dark web, however, is roughly 5% of the deep web, and it is intentionally hidden and is only accessible using an anonymizing web browser such as Tor. Due to its anonymous nature that conceals users’ identities, the dark web is a common marketplace for stolen data and illegal activities. Monitoring the dark web for the illicit exchange and sale of personal and organizational data is a common part of an overall cybersecurity defense strategy.