Encyclopedia of Computer Science and Technology

Web browser 503• platforms for user-created content and collaboration(see blogs and blogging, social networking, andwikis and Wikipedia)In some quarters the term Web 2.0 is already obsoleteor relegated to a marketing buzzword, while the search ison for new ways to describe the latest developments suchas, inevitably, “Web 3.0.” One possible emphasis movingbeyond Web 2.0 is the leveraging of the actual knowledgecontained in Web pages, properly encoded and interpretedby applications (see semantic web and software agent).Whatever terminology might be used, the importantthing is that people are using the Web in the late 2000decade in substantially new ways, and that the consequencesare likely to spread beyond the online world tosociety as a whole.Further ReadingFost, Dan. “Digital Utopia: A New Breed of Technologists Envisionsa Democratic World Improved by the Internet.” SanFrancisco Chronicle, November 5, 2006, p. F1. Availableonline. URL: http://sfgate.com/cgi-bin/article.cgi?file=/c/a/2006/11/05/BUGIGM5A2D1.DTL. Accessed December 4,2007.———. “The People Who Populate Web 2.0” San FranciscoChronicle, November 5, 2006, p. F5. Available online. URL:http://sfgate.com/cgi-bin/article.cgi?file=/c/a/2006/11/05/BUG78M5OUA1.DTL. Accessed December 4, 2007.Madden, Mary, and Susannah Fox. “Riding the Waves of ‘Web2.0.’ ” Pew Internet & American Life Project, October 5, 2006.Available online. URL: http://www.pewinternet.org/pdfs/PIP_Web_2.0.pdf. Accessed December 4, 2007.Metz, Cade. “Web 3.0.” PC Magazine, March 14, 2007. Available online.URL: http://www.pcmag.com/article2/0,1759,2102852,00.asp.Accessed December 4, 2007.Solomon, Gwen, and Lynne Schrum. Web 2.0: New Tools, NewSchools. Eugene, Ore.: ISTE, 2007.Vossen, Gottfried, and Stephan Hagemann. Unleashing Web 2.0:From Concepts to Creativity. Burlington, Mass.: MorganKaufmann, 2007.When the Web was first created in the early 1990s (seeBerners-Lee, Tim) it consisted only of text pages, althoughthere were a few experimental graphical Web extensionsdeveloped by various researchers. The first graphical Webbrowser to achieve widespread use was Mosaic created byMarc Andreessen, developed at the National Center forSupercomputing Applications (NCSA). (See Andreessen,Marc.) By 1993, Mosaic was available for free downloadand had become the browser of choice for PC users.Andreessen left NCSA in 1994 to found Netscape Corporation.The Netscape Navigator browser improved Mosaicin several ways, making the graphics faster and more attractive.Netscape included a facility called Secure SocketsLayer (SSL) for carrying out encrypted commercial transactionson-line (see e-commerce).Microsoft, which had been a latecomer to the Internetboom, entered the fray with its Microsoft Internet Explorer.At first the program was inferior to Netscape, but it wassteadily improved. Aided by Microsoft’s controversial tactic ofbundling the free browser starting with Windows 95, InternetExplorer has taken over the leading browser position withWeb browserThe World Wide Web consists of millions of sites (seeWorld Wide Web and Web server) that provide hypertextdocuments (see html and Web page design) that caninclude not only text but still images, video, and sound. Toaccess these pages, the user runs a Web-browsing program.The basic function of a Web browser is to request apage by specifying its address (URL, uniform [or universal]resource locator). This request resolves to a request (HTTP,HyperText Transport Protocol) that is processed by the relevantWeb server. The server sends the HTML document tothe browser, which then displays it for the user. Typically,the browser stores recently requested documents and filesin a local cache on the user’s PCs. Use of the cache reducesthe amount of data that must be resent over the Internet.However, sufficiently skilled snoopers can examine thecache to find details of a user’s recent Web surfing. (Cachingis also used by Internet Service Providers so they canprovide frequently requested pages from their own serverrather than having to fetch them from the hosting sites.)A Web browser such as Microsoft Internet Explorer or Firefoxmakes it easy to find and move between linked Web pages. Browserusers can record or “bookmark” favorite pages. Browser plug-insprovide support for services such as streaming video and audio.Here, part of the photo library of the National Oceanic and AtmosphericAdministration is shown. (NOAA image)