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Web2 0-ppt-100604064305-phpapp02

  1. 1. WEB 2.0Name of presentationby Mr R.RAJAVEL(MAGNA COLLEGE OF ENGINEERING) Page 1
  2. 2. The term "Web 2.0" is commonly associated with web applications thatfacilitate interactive information sharing, interoperability,user-centered design,[1] and collaboration on the World Wide Web. AWeb 2.0 site allows its users to interact with each other as contributors tothe websites content, in contrast to websites where users are limited tothe passive viewing of information that is provided to them. Examples ofWeb 2.0 include web-based communities, hosted services,web applications, social-networking sites, video-sharing sites, wikis, blogs, mashups, and folksonomies.The term is closely associated with Tim OReilly because of theOReilly Media Web 2.0 conference in 2004.[2][3] Although the termsuggests a new version of the World Wide Web, it does not refer to anupdate to any technical specifications, but rather to cumulative changesin the ways software developers and end-users use the Web. WhetherWeb 2.0 is qualitatively different from prior web technologies has beenchallenged by World Wide Web inventor Tim Berners-Lee, who called theterm a "piece of jargon"[4] — precisely because he specifically intendedthe Web to embody these values in the first place. Page 2
  3. 3. History:The term "Web 2.0" was coined in 1999 by Darcy DiNucci. In her article, "Fragmented Future," DiNucciwrites:[5]The Web we know now, which loads into a browser window in essentially static screenfulls, is only anembryo of the Web to come. The first glimmerings of Web 2.0 are beginning to appear, and we are juststarting to see how that embryo might develop. The Web will be understood not as screenfulls of text andgraphics but as a transport mechanism, the ether through which interactivity happens. It will [...] appear onyour computer screen, [...] on your TV set [...] your car dashboard [...] your cell phone [...] hand-held gamemachines [...] maybe even your microwave oven.Her use of the term deals mainly with Web design and aesthetics; she argues that the Web is "fragmenting"due to the widespread use of portable Web-ready devices. Her article is aimed at designers, remindingthem to code for an ever-increasing variety of hardware. As such, her use of the term hints at – but doesnot directly relate to – the current uses of the term.The term did not resurface until 2003.[6][7][8] These authors focus on the concepts currently associatedwith the term where, as Scott Dietzen puts it, "the Web becomes a universal, standards-based integrationplatform".[9]In 2004, the term began its rise in popularity when OReilly Media and MediaLive hosted the first Web 2.0conference. In their opening remarks, John Battelle and Tim OReilly outlined their definition of the "Web asPlatform", where software applications are built upon the Web as opposed to upon the desktop. The uniqueaspect of this migration, they argued, is that "customers are building your business for you".[10] Theyargued that the activities of users generating content (in the form of ideas, text, videos, or pictures) could be"harnessed" to create value. Page 3
  4. 4. Netscape framed "the web as platform" in terms of the old software paradigm: theirflagship product was the web browser, a desktop application, and their strategy was to usetheir dominance in the browser market to establish a market for high-priced serverproducts. Control over standards for displaying content and applications in the browserwould, in theory, give Netscape the kind of market power enjoyed by Microsoft in the PCmarket. Much like the "horseless carriage" framed the automobile as an extension of thefamiliar, Netscape promoted a "webtop" to replace the desktop, and planned to populatethat webtop with information updates and applets pushed to the webtop by informationproviders who would purchase Netscape servers.[11]In short, Netscape focused on creating software, updating it on occasion, and distributingit to the end users. OReilly contrasted this with Google, a company which did not at thetime focus on producing software, such as a browser, but instead focused on providing aservice based on data. The data being the links Web page authors make between sites.Google exploits this user-generated content to offer Web search based on reputationthrough its "page rank" algorithm. Unlike software, which undergoes scheduled releases,such services are constantly updated, a process called "the perpetual beta".A similar difference can be seen between the Encyclopedia Britannica Online andWikipedia: while the Britannica relies upon experts to create articles and releases themperiodically in publications, Wikipedia relies on trust in anonymous users to constantly andquickly build content. Wikipedia is not based on expertise but rather an adaptation of theopen source software adage "given enough eyeballs, all bugs are shallow", and itproduces and updates articles constantly. Page 4
  5. 5. Characteristics Flickr, a Web 2.0 web site that allows its users to upload and share photosWeb 2.0 websites allow users to do more than just retrieve information. They can build onthe interactive facilities of "Web 1.0" to provide "Network as platform" computing, allowingusers to run software-applications entirely through a browser.[3] Users can own the dataon a Web 2.0 site and exercise control over that data.[3][14] These sites may have an"Architecture of participation" that encourages users to add value to the application asthey use it.[2][3]The concept of Web-as-participation-platform captures many of these characteristics. BartDecrem, a founder and former CEO of Flock, calls Web 2.0 the "participatory Web"[15]and regards the Web-as-information-source as Web 1.0.The impossibility of excluding group-members who don’t contribute to the provision ofgoods from sharing profits gives rise to the possibility that rational members will prefer towithhold their contribution of effort and free-ride on the contribution of others.[16] Thisrequires what is sometimes called Radical Trust by the management of the website.According to Best,[17] the characteristics of Web 2.0 are: rich user experience, userparticipation, dynamic content, metadata, web standards and scalability. Furthercharacteristics, such as openness, freedom[18] and collective intelligence[19] by way of Page 5user participation, can also be viewed as essential attributes of Web 2.0.
  6. 6. Technology overviewWeb 2.0 draws together the capabilities of client- and server-side software, content syndication and the use ofnetwork protocols. Standards-oriented web browsers may useplug-ins and software extensions to handle the content andthe user interactions. Web 2.0 sites provide users withinformation storage, creation, and dissemination capabilitiesthat were not possible in the environment now known as "Web1.0".Web 2.0 websites typically include some of the followingfeatures and techniques. Andrew McAfee used the acronymSLATES to refer to them:[20] Page 6
  7. 7. Search: Finding information through keyword search.Links: Connects information together into a meaningful information ecosystem using the model of the Web, andprovides low-barrier social tools.Authoring: The ability to create and update content leads to the collaborative work of many rather than just a fewweb authors. In wikis, users may extend, undo and redo each others work. In blogs, posts and the comments ofindividuals build up over time.Tags: Categorization of content by users adding "tags" - short, usually one-word descriptions - to facilitatesearching, without dependence on pre-made categories. Collections of tags created by many users within a singlesystem may be referred to as "folksonomies" (i.e., folk taxonomies).Extensions: Software that makes the Web an application platform as well as a document server.Signals: The use of syndication technology such as RSS to notify users of content changes.While SLATES forms the basic framework of Enterprise 2.0, it does not contradict all of the higher level Web 2.0design patterns and business models. And in this way, the new Web 2.0 report from OReilly is quite effective anddiligent in interweaving the story of Web 2.0 with the specific aspects of Enterprise 2.0. It includes discussions ofself-service IT, the long tail of enterprise IT demand, and many other consequences of the Web 2.0 era in theenterprise. The report also makes many sensible recommendations around starting small with pilot projects andmeasuring results, among a fairly long list. [21] Page 7
  8. 8. How it worksThe client-side/web browser technologies typically used in Web 2.0 development are AsynchronousJavaScript and XML (Ajax), Adobe Flash and the Adobe Flex framework, and JavaScript/Ajaxframeworks such as Yahoo! UI Library, Dojo Toolkit, MooTools, and jQuery. Ajax programming usesJavaScript to upload and download new data from the web server without undergoing a full pagereload.To permit the user to continue to interact with the page, communications such as data requests goingto the server are separated from data coming back to the page (asynchronously). Otherwise, the userwould have to routinely wait for the data to come back before they can do anything else on that page,just as a user has to wait for a page to complete the reload. This also increases overall performanceof the site, as the sending of requests can complete quicker independent of blocking and queueingrequired to send data back to the client.The data fetched by an Ajax request is typically formatted in XML or JSON (JavaScript ObjectNotation) format, two widely used structured data formats. Since both of these formats are nativelyunderstood by JavaScript, a programmer can easily use them to transmit structured data in their webapplication. When this data is received via Ajax, the JavaScript program then uses theDocument Object Model (DOM) to dynamically update the web page based on the new data, allowingfor a rapid and interactive user experience. In short, using these techniques, Web designers canmake their pages function like desktop applications. For example, Google Docs uses this techniqueto create a Web-based word processor. Page 8
  9. 9. UsageThe popularity of the term Web 2.0, along with the increasing use of blogs, wikis, and socialnetworking technologies, has led many in academia and business to coin a flurry of 2.0s,[23]including Library 2.0,[24] Social Work 2.0,[25] Enterprise 2.0, PR 2.0,[26] Classroom 2.0, Publishing2.0, Medicine 2.0, Telco 2.0, Travel 2.0, Government 2.0,[27] and even Porn 2.0.[28] Many of these2.0s refer to Web 2.0 technologies as the source of the new version in their respective disciplines andareas. For example, in the Talis white paper "Library 2.0: The Challenge of Disruptive Innovation",Paul Miller arguesBlogs, wikis and RSS are often held up as exemplary manifestations of Web 2.0. A reader of a blogor a wiki is provided with tools to add a comment or even, in the case of the wiki, to edit the content.This is what we call the Read/Write web.Talis believes that Library 2.0 means harnessing this type ofparticipation so that libraries can benefit from increasingly rich collaborative cataloguing efforts, suchas including contributions from partner libraries as well as adding rich enhancements, such as bookjackets or movie files, to records from publishers and others.[29]Here, Miller links Web 2.0 technologies and the culture of participation that they engender to the fieldof library science, supporting his claim that there is now a "Library 2.0". Many of the other proponentsof new 2.0s mentioned here use similar methods. Page 9
  10. 10. ATOMThe name Atom applies to a pair of related standards. The Atom Syndication Format is anXML language used for web feeds, while the Atom Publishing Protocol (AtomPub or APP)is a simple HTTP-based protocol for creating and updating web resources.Web feeds allow software programs to check for updates published on a website. Toprovide a web feed, a site owner may use specialized software (such as acontent management system) that publishes a list (or "feed") of recent articles or contentin a standardized, machine-readable format. The feed can then be downloaded bywebsites that syndicate content from the feed, or by feed reader programs that allowInternet users to subscribe to feeds and view their content.A feed contains entries, which may be headlines, full-text articles, excerpts, summaries,and/or links to content on a website, along with various metadata.The Atom format was developed as an alternative to RSS. Ben Trott, an advocate of thenew format that became Atom, believed that RSS had limitations and flaws—such as lackof on-going innovation and its necessity to remain backward compatible— and that therewere advantages to a fresh design.[1] Page 10
  11. 11. UsageWeb feeds are used by the blogging community to share recent entries headlines, full text, and evenattached multimedia files.[2] These providers allow other websites to incorporate the blogs"syndicated" headline or headline-and-short-summary feeds under various usage agreements. Atomand other web syndication formats are now used for many purposes, including journalism, marketing,bug-reports, or any other activity involving periodic updates or publications. Atom also provides astandard way to export an entire blog, or parts of it, for backup or for importing into other bloggingsystems.It is common to find web feeds on major Web sites, as well as many smaller ones. Some websites letpeople choose between RSS or Atom formatted web feeds; others offer only RSS or only Atom. Inparticular, many blog and wiki sites offer their web feeds in the Atom format.A feed reader or "aggregator" program can be used to check feeds and display new articles.Client-side readers may also be designed as standalone programs or as extensions to existingprograms like web browsers. Browsers are moving toward integrated feed reader functions.Web-based feed readers and news aggregators require no software installation and make the users"feeds" available on any computer with Web access. Some aggregators syndicate (combine) webfeeds into new feeds, e.g., taking all football related items from several sports feeds and providing anew football feed. There are also several search engines for web feed content[citation needed]. Page 11
  12. 12. RSSRSS (most commonly expanded as Really Simple Syndication) is a family of web feed formats usedto publish frequently updated works—such as blog entries, news headlines, audio, and video—in astandardized format.[2] An RSS document (which is called a "feed", "web feed",[3] or "channel")includes full or summarized text, plus metadata such as publishing dates and authorship. Web feedsbenefit publishers by letting them syndicate content automatically. They benefit readers who want tosubscribe to timely updates from favored websites or to aggregate feeds from many sites into oneplace. RSS feeds can be read using software called an "RSS reader", "feed reader", or "aggregator",which can be web-based, desktop-based, or mobile-device-based. A standardized XML file formatallows the information to be published once and viewed by many different programs. The usersubscribes to a feed by entering into the reader the feeds URI or by clicking an RSS icon in a webbrowser that initiates the subscription process. The RSS reader checks the users subscribed feedsregularly for new work, downloads any updates that it finds, and provides a user interface to monitorand read the feeds.RSS formats are specified using XML, a generic specification for the creation of data formats.Although RSS formats have evolved from as early as March 1999,[4] it was between 2005 and 2006when RSS gained widespread use, and the ("") icon was decided upon by several major Webbrowsers.[5] Page 12
  13. 13. HistoryMain article: History of web syndication technologyThe RSS formats were preceded by several attempts at web syndication that did not achievewidespread popularity. The basic idea of restructuring information about websites goes back to asearly as 1995, when Ramanathan V. Guha and others in Apple ComputersAdvanced Technology Group developed the Meta Content Framework.[6] For a more detaileddiscussion of these early developments, see the history of web syndication technology.RDF Site Summary, the first version of RSS, was created by Guha at Netscape in March 1999 for useon the My.Netscape.Com portal. This version became known as RSS 0.9.[4] In July 1999, Dan Libbyof Netscape produced a new version, RSS 0.91,[2] which simplified the format by removing RDFelements and incorporating elements from Dave Winers scriptingNews syndication format.[7] Libbyalso renamed RSS "Rich Site Summary" and outlined further development of the format in a "futuresdocument".[8]This would be Netscapes last participation in RSS development for eight years. As RSS was beingembraced by web publishers who wanted their feeds to be used on My.Netscape.Com and other earlyRSS portals, Netscape dropped RSS support from My.Netscape.Com in April 2001 during new ownerAOLs restructuring of the company, also removing documentation and tools that supported theformat.[9] Page 13
  14. 14. VariantsThere are several different versions of RSS, falling into two major branches (RDF and 2.*).The RDF (or RSS 1.*) branch includes the following versions:RSS 0.90 was the original Netscape RSS version. This RSS was called RDF Site Summary, but was based on anearly working draft of the RDF standard, and was not compatible with the final RDF Recommendation.RSS 1.0 is an open format by the RSS-DEV Working Group, again standing for RDF Site Summary. RSS 1.0 is anRDF format like RSS 0.90, but not fully compatible with it, since 1.0 is based on the final RDF 1.0Recommendation.RSS 1.1 is also an open format and is intended to update and replace RSS 1.0. The specification is anindependent draft not supported or endorsed in any way by the RSS-Dev Working Group or any other organization.The RSS 2.* branch (initially UserLand, now Harvard) includes the following versions:RSS 0.91 is the simplified RSS version released by Netscape, and also the version number of the simplified versionoriginally championed by Dave Winer from Userland Software. The Netscape version was now called Rich SiteSummary; this was no longer an RDF format, but was relatively easy to use.RSS 0.92 through 0.94 are expansions of the RSS 0.91 format, which are mostly compatible with each other andwith Winers version of RSS 0.91, but are not compatible with RSS 0.90.RSS 2.0.1 has the internal version number 2.0. RSS 2.0.1 was proclaimed to be "frozen", but still updated shortlyafter release without changing the version number. RSS now stood for Really Simple Syndication. The major 14 Pagechange in this version is an explicit extension mechanism using XML namespaces.[21]
  15. 15. ModulesThe primary objective of all RSS modules is to extend the basic XMLschema established for more robust syndication of content. Thisinherently allows for more diverse, yet standardized, transactions withoutmodifying the core RSS specification.To accomplish this extension, a tightly controlled vocabulary (in the RSSworld, "module"; in the XML world, "schema") is declared through anXML namespace to give names to concepts and relationships betweenthose concepts.Some RSS 2.0 modules with established namespaces are:Ecommerce RSS 2.0 ModuleMedia RSS 2.0 ModuleOpenSearch RSS 2.0 Module Page 15