Web 2.0 Portals and Technology Overview

"Web 2.0" refers to web development and web design that facilitates interactive information sharing, interoperability, user-centered design and collaboration on the World Wide Web. Examples of Web 2.0 include web-based communities, hosted services, web applications, social-networking sites, video-sharing sites, wikis, blogs, mashups and folksonomies. A Web 2.0 site allows its users to interact with other users or to change website content, in contrast to non-interactive websites where users are limited to the passive viewing of information that is provided to them.

The term is closely associated with Tim O'Reilly because of the O'Reilly Media Web 2.0 conference in 2004. Although the term suggests a new version of the World Wide Web, it does not refer to an update to any technical specifications, but rather to cumulative changes in the ways software developers and end-users use the Web. Whether Web 2.0 is qualitatively different from prior web technologies has been challenged by World Wide Web inventor Tim Berners-Lee who called the term a "piece of jargon".

The sometimes complex and continually evolving technology infrastructure of Web 2.0 includes server-software, content-syndication, messaging-protocols, standards-oriented browsers with plugins and extensions, and various client-applications. The differing, yet complementary approaches of such elements provide Web 2.0 sites with information-storage, creation, and dissemination challenges and capabilities that go beyond what the public formerly expected in the environment of the so-called "Web 1.0".

Web 2.0 websites typically include some of the following features/techniques. Andrew McAfee used the acronym SLATES to refer to them:[19]

Search

The ease of finding information through keyword search.

Links

Ad-hoc guides to other relevant information.

Authoring

The ability to create constantly updating content over a platform that is shifted from being the creation of a few to being constantly updated, interlinked work. In wikis, the content is iterative in the sense that users undo and redo each other's work. In blogs, content is cumulative in that posts and comments of individuals are accumulated over time.

Tags

Categorization of content by creating tags: simple, one-word user-determined descriptions to facilitate searching and avoid rigid, pre-made categories.

Extensions

Powerful algorithms that leverage the Web as an application platform as well as a document server.

Signals

The use of RSS technology to rapidly notify users of content changes.

Ajax has prompted the development of websites that mimic desktop applications, such as word processing, the spreadsheet, and slide-show presentation. WYSIWYG wiki sites replicate many features of PC authoring applications. Still other sites perform collaboration and project management functions. In 2006 Google, Inc. acquired one of the best-known sites of this broad class, Writely.[27]

Several browser-based "operating systems" have emerged, including EyeOS[28] and YouOS.[29] Although coined as such, many of these services function less like a traditional operating system and more as an application platform. They mimic the user experience of desktop operating-systems, offering features and applications similar to a PC environment, as well as the added ability of being able to run within any modern browser. However, these operating systems do not control the hardware on the client's computer.

Numerous web-based application services appeared during the dot-com bubble of 1997–2001 and then vanished, having failed to gain a critical mass of customers. In 2005, WebEx acquired one of the better-known of these, Intranets.com, for $45 million.[30]

Internet applications

XML and RSS

Advocates of "Web 2.0" may regard syndication of site content as a Web 2.0 feature, involving as it does standardized protocols, which permit end-users to make use of a site's data in another context (such as another website, a browser plugin, or a separate desktop application). Protocols which permit syndication include RSS (Really Simple Syndication — also known as "web syndication"), RDF (as in RSS 1.1), and Atom, all of them XML-based formats. Observers have started to refer to these technologies as "Web feed" as the usability of Web 2.0 evolves and the more user-friendly Feeds icon supplants the RSS icon.

Specialized protocols

Specialized protocols such as FOAF and XFN (both for social networking) extend the functionality of sites or permit end-users to interact without centralized websites.

Other protocols, like Jabber enables services to users like Services over the Messenger

Web APIs

Machine-based interaction, a common feature of Web 2.0 sites, uses two main approaches to Web APIs, which allow web-based access to data and functions: REST and SOAP.

1. REST (Representational State Transfer) Web APIs use HTTP alone to interact, with XML (eXtensible Markup Language) or JSON payloads;
2. SOAP involves POSTing more elaborate XML messages and requests to a server that may contain quite complex, but pre-defined, instructions for the server to follow.

Often servers use proprietary APIs, but standard APIs (for example, for posting to a blog or notifying a blog update) have also come into wide use. Most communications through APIs involve XML or JSON payloads.

See also Web Services Description Language (WSDL) (the standard way of publishing a SOAP API) and this list of Web Service specifications.