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InfoSkills for Social and Behavioral Sciences

InfoSkills @ TiU

The layers of the web

The surface web

Most of us use the top layer of the internet, the so-called surface web – also called the visible, public, or open web – on a daily basis. This includes everything that can be easily found through search engines like Google or Bing.

How Google indexes the web
Find out by watching this short 5-minute video.

Source: Google.

The deep web

Source: Pere [Adapted]. Published under a CC BY-NC-SA 2.0 license. 

Beneath the surface web lies a much larger, hidden layer known as the deep web. This includes millions of pages containing financial records, academic databases, private social media content, subscription-only articles, and other data that is not publicly accessible. The deep web consists of content that search engines can’t index – meaning you won’t find it through a Google search. You access deep web content when you log into your email, use online banking, or search within a website’s internal database. These pages are hidden behind login forms or search boxes, preventing search engine crawlers from accessing them.

Additional examples of deep web content include: 

  • Paid content, such as digital newspapers.
  • Websites requiring user registration for access.
  • Private data like cloud storage and email accounts.
  • Online learning platforms (e.g., Canvas).
  • Personal profiles on social media set to private.
  • Sites that require CAPTCHA verification before granting access.
  • Private networks (intranets) used by companies, governments, schools, and universities, which restrict access to authorized users only
  • Dynamic web pages that generate content on demand (e.g., product listings generated by online store searches).
  • Subscription-based (paywalled) scholarly sources available through library databases. Access is typically limited to students and staff at well-funded universities, which creates a barrier for many potential users – such as students and researchers from universities in lower-income countries.

The dark web

The dark web is a small portion of the deep web that is intentionally hidden and requires special software to access. While some people use the dark web for privacy-related purposes – such as whistleblowing or political activism – it is also known as a hub for illegal activities, including black market trading (e.g., drugs and weapons), the distribution of illegal content, and services related to fraud and identity theft.

Open access

Source: Gideon Burton. Published under a CC BY-SA 2.0 license.

Open access is a global academic movement that promotes free and unrestricted online access to scholarly research. Unlike the traditional subscription-based publishing model – where libraries or individual readers pay for access – open access ensures that research is available to everyone, without financial or legal barriers. When content is open access, it is often marked with the open access icon 

How can researchers make their work open access?

  1. Self-archiving (green open access)
    Researchers can deposit a version of their article in an institutional repository. This is usually the postprint — the peer-reviewed manuscript accepted for publication but not yet copy-edited or formatted. An institutional repository is a digital archive maintained by universities to store and share research. This makes the work freely accessible, often after an embargo period set by the publisher. Self-archiving is a cost-effective and widely used open access route.

  2. Open access publishing (gold or hybrid open access)

    Researchers can publish their final, peer-reviewed articles through gold open access, where articles are made freely and permanently available to all readers immediately upon publication. Gold open access journals typically charge authors a fee to cover publishing costs.

    Alternatively, authors can publish in hybrid journals – traditional subscription-based journals that offer the option to make individual articles open access for a fee.

Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License by Tilburg University.