The Deep Web includes content on the Internet that is not indexed by traditional search engines like Google or Bing; paste sites that require a direct link and protected content sites such as Dropbox are a few familiar examples. The Dark Web is considered part of the Deep Web, with the distinction that the content has been intentionally hidden and requires special browsers to access. While not everything on the Dark Web is illicit, the anonymity it provides makes it an ideal place for criminal activity.
The Centre for International Governance Innovation’s (CIGI) whitepaper is an excellent primer on the Dark Web and its impact on cybersecurity. Authors Chertoff and Simon state, “...it has become increasingly important for security agencies to track and monitor the activities in the dark Web,” concluding, “Security researchers have to remain vigilant and find new ways to spot upcoming malicious services to deal with new phenomena as quickly as possible.”