The deep web, [1] invisible web, [2] or hidden web [3] are parts of the World Wide Web whose contents are not indexed by standard web search-engine programs. This is in contrast to the "surface web", which is accessible to anyone using the Internet. [4] Computer scientist Michael K. Bergman is credited with inventing the term in 2001 as a search-indexing term. [5]
Deep web sites can be accessed by a direct URL or IP address, but may require entering a password or other security information to access actual content. [6] [7] Uses of deep web sites include web mail, online banking, cloud storage, restricted-access social-media pages and profiles, and web forums that require registration for viewing content. It also includes paywalled services such as video on demand and some online magazines and newspapers.
The first conflation of the terms "deep web" and "dark web" happened during 2009 when deep web search terminology was discussed together with illegal activities occurring on the Freenet and darknet. [8] Those criminal activities include the commerce of personal passwords, false identity documents, drugs, firearms, and child pornography. [9]
Since then, after their use in the media's reporting on the black-market website Silk Road, media outlets have generally used 'deep web' synonymously with the dark web or darknet, a comparison some reject as inaccurate [10] and consequently has become an ongoing source of confusion. [11] Wired reporters Kim Zetter [12] and Andy Greenberg [13] recommend the terms be used in distinct fashions. While the deep web is a reference to any site that cannot be accessed by a traditional search engine, the dark web is a portion of the deep web that has been hidden intentionally and is inaccessible by standard browsers and methods. [14] [15] [16] [17] [18]
Bergman, in a paper on the deep web published in The Journal of Electronic Publishing, mentioned that Jill Ellsworth used the term Invisible Web in 1994 to refer to websites that were not registered with any search engine. [19] Bergman cited a January 1996 article by Frank Garcia: [20]
It would be a site that's possibly reasonably designed, but they didn't bother to register it with any of the search engines. So, no one can find them! You're hidden. I call that the invisible Web.
Another early use of the term Invisible Web was by Bruce Mount and Matthew B. Koll of Personal Library Software, in a description of the No. 1 Deep Web program found in a December 1996 press release. [21]
The first use of the specific term deep web, now generally accepted, occurred in the aforementioned 2001 Bergman study. [19]
Methods that prevent web pages from being indexed by traditional search engines may be categorized as one or more of the following:
While it is not always possible to discover directly a specific web server's content so that it may be indexed, a site potentially can be accessed indirectly (due to computer vulnerabilities).
To discover content on the web, search engines use web crawlers that follow hyperlinks through known protocol virtual port numbers. This technique is ideal for discovering content on the surface web but is often ineffective at finding deep web content. For example, these crawlers do not attempt to find dynamic pages that are the result of database queries due to the indeterminate number of queries that are possible. [26] It has been noted that this can be overcome (partially) by providing links to query results, but this could unintentionally inflate the popularity of a site of the deep web.
DeepPeep, Intute, Deep Web Technologies, Scirus, and Ahmia.fi are a few search engines that have accessed the deep web. Intute ran out of funding and is now a temporary static archive as of July 2011. [27] Scirus retired near the end of January 2013. [28]
Researchers have been exploring how the deep web can be crawled in an automatic fashion, including content that can be accessed only by special software such as Tor. In 2001, Sriram Raghavan and Hector Garcia-Molina (Stanford Computer Science Department, Stanford University) [29] [30] presented an architectural model for a hidden-Web crawler that used important terms provided by users or collected from the query interfaces to query a Web form and crawl the Deep Web content. Alexandros Ntoulas, Petros Zerfos, and Junghoo Cho of UCLA created a hidden-Web crawler that automatically generated meaningful queries to issue against search forms. [31] Several form query languages (e.g., DEQUEL [32] ) have been proposed that, besides issuing a query, also allow extraction of structured data from result pages. Another effort is DeepPeep, a project of the University of Utah sponsored by the National Science Foundation, which gathered hidden-web sources (web forms) in different domains based on novel focused crawler techniques. [33] [34]
Commercial search engines have begun exploring alternative methods to crawl the deep web. The Sitemap Protocol (first developed, and introduced by Google in 2005) and OAI-PMH are mechanisms that allow search engines and other interested parties to discover deep web resources on particular web servers. Both mechanisms allow web servers to advertise the URLs that are accessible on them, thereby allowing automatic discovery of resources that are not linked directly to the surface web. Google's deep web surfacing system computes submissions for each HTML form and adds the resulting HTML pages into the Google search engine index. The surfaced results account for a thousand queries per second to deep web content. [35] In this system, the pre-computation of submissions is done using three algorithms:
In 2008, to facilitate users of Tor hidden services in their access and search of a hidden .onion suffix, Aaron Swartz designed Tor2web—a proxy application able to provide access by means of common web browsers. [36] Using this application, deep web links appear as a random sequence of letters followed by the .onion top-level domain.
In computing, a search engine is an information retrieval software system designed to help find information stored on one or more computer systems. Search engines discover, crawl, transform, and store information for retrieval and presentation in response to user queries. The search results are usually presented in a list and are commonly called hits. The most widely used type of search engine is a web search engine, which searches for information on the World Wide Web.
A Web crawler, sometimes called a spider or spiderbot and often shortened to crawler, is an Internet bot that systematically browses the World Wide Web and that is typically operated by search engines for the purpose of Web indexing.
In computer network communications, the HTTP 404, 404 not found, 404, 404 error, page not found, or file not found error message is a hypertext transfer protocol (HTTP) standard response code, to indicate that the browser was able to communicate with a given server, but the server could not find what was requested. The error may also be used when a server does not wish to disclose whether it has the requested information.
Spamdexing is the deliberate manipulation of search engine indexes. It involves a number of methods, such as link building and repeating unrelated phrases, to manipulate the relevance or prominence of resources indexed in a manner inconsistent with the purpose of the indexing system.
CiteSeerX is a public search engine and digital library for scientific and academic papers, primarily in the fields of computer and information science.
Search engine optimization (SEO) is the process of improving the quality and quantity of website traffic to a website or a web page from search engines. SEO targets unpaid traffic rather than direct traffic or paid traffic. Unpaid traffic may originate from different kinds of searches, including image search, video search, academic search, news search, and industry-specific vertical search engines.
Internet research is the practice of using Internet information, especially free information on the World Wide Web, or Internet-based resources in research.
A metasearch engine is an online information retrieval tool that uses the data of a web search engine to produce its own results. Metasearch engines take input from a user and immediately query search engines for results. Sufficient data is gathered, ranked, and presented to the users.
A dark net or darknet is an overlay network within the Internet that can only be accessed with specific software, configurations, or authorization, and often uses a unique customized communication protocol. Two typical darknet types are social networks, and anonymity proxy networks such as Tor via an anonymized series of connections.
Google Scholar is a freely accessible web search engine that indexes the full text or metadata of scholarly literature across an array of publishing formats and disciplines. Released in beta in November 2004, the Google Scholar index includes peer-reviewed online academic journals and books, conference papers, theses and dissertations, preprints, abstracts, technical reports, and other scholarly literature, including court opinions and patents.
A search engine is a software system that provides hyperlinks to web pages and other relevant information on the Web in response to a user's query. The user inputs a query within a web browser or a mobile app, and the search results are often a list of hyperlinks, accompanied by textual summaries and images. Users also have the option of limiting the search to a specific type of results, such as images, videos, or news.
Web archiving is the process of collecting portions of the World Wide Web to ensure the information is preserved in an archive for future researchers, historians, and the public. Web archivists typically employ web crawlers for automated capture due to the massive size and amount of information on the Web. The largest web archiving organization based on a bulk crawling approach is the Wayback Machine, which strives to maintain an archive of the entire Web.
DeepPeep was a search engine that aimed to crawl and index every database on the public Web. Unlike traditional search engines, which crawl existing webpages and their hyperlinks, DeepPeep aimed to allow access to the so-called Deep web, World Wide Web content only available via for instance typed queries into databases. The project started at the University of Utah and was overseen by Juliana Freire, an associate professor at the university's School of Computing WebDB group. The goal was to make 90% of all WWW content accessible, according to Freire. The project ran a beta search engine and was sponsored by the University of Utah and a $243,000 grant from the National Science Foundation. It generated worldwide interest.
The following outline is provided as an overview of and topical guide to search engines.
The Hidden Wiki was a dark web MediaWiki wiki operating as Tor hidden services that could be anonymously edited after registering on the site. The main page served as a directory of links to other .onion sites.
The dark web is the World Wide Web content that exists on darknets: overlay networks that use the Internet but require specific software, configurations, or authorization to access. Through the dark web, private computer networks can communicate and conduct business anonymously without divulging identifying information, such as a user's location. The dark web forms a small part of the deep web, the part of the web not indexed by web search engines, although sometimes the term deep web is mistakenly used to refer specifically to the dark web.
Grams is a discontinued search engine for Tor based darknet markets launched in April 2014, and closed in December 2017. The service allowed users to search multiple darknet markets for products like drugs and guns from a simple search interface, and also provided the capability for its users to hide their transactions through its bitcoin tumbler Helix.
Clearnet is a term that typically refers to the publicly accessible Internet. Sometimes "clearnet" is used as a synonym for "surface web"—excluding both the darknet and the deep web. The World Wide Web is one of the most popular distributed services on the Internet, and the surface web is composed of the web pages and databases that are indexed by traditional search engines.
Ahmia is a clearnet search engine for Tor's hidden services created by Juha Nurmi.
Netstalking is a searching activity carried out within the limits of Internet, aimed at finding little-known, inaccessible, forbidden, shocking and rarely-visited objects, including their analysis, systematisation and storage. The objects found are either aesthetically pleasing or informationally fulfilling to a seeker.
[...] Mike Bergman, a computer scientist and consultant who is credited with coining the term Deep Web.
There are other simpler versions of Memex already available. "If you've ever used the Internet Archive's Wayback Machine", which gives you past versions of a website not accessible through Google, then you've technically searched the Deep Web, said Chris Mattmann.
by end of January 2014, Elsevier will be discontinuing Scirus, its free science search engine. Scirus has been a wide-ranging research tool, with over 575 million items indexed for searching, including webpages, pre-print articles, patents, and repositories.
{{cite journal}}: Cite journal requires |journal= (help){{cite journal}}: Cite journal requires |journal= (help){{cite journal}}: Cite journal requires |journal= (help){{cite journal}}: Cite journal requires |journal= (help){{cite journal}}: Cite journal requires |journal= (help)
