We refer to any online content that is easily searchable as the "Open Web". This includes material found using search engines, news publications and all social media.
The opposite of the Open Web is often called the Deep Web or Dark Web and is made up of networks that require special tools or encryption to access.
For the purposes of this class, we'll refer to the Open Web as everything that is freely available or accessible online without hitting a paywall. You could also think about it as free online content or information.
The video below explains more.