Web 2.0, also called Participative (or Participatory) and Social Web, refers to World Wide Web websites that emphasize user-generated content, usability (ease of use, even by non-experts), participatory culture and interoperability (this means that a website can work well with other products, systems, and devices) for end users. A Web 2.0 website may allow users to interact and collaborate with each other in a social media dialogue as creators of user-generated content in a virtual community, in contrast to the first generation of Web 1.0-era websites where people were limited to the passive viewing of content.

Conversational or two-way media is a key characteristic of so-called Web 2.0 which encourages the publishing of one's own content and commenting on other people's content.

The term was invented by Darcy DiNucci in 1999 and popularized several years later by Tim O'Reilly and Dale Dougherty at the O'Reilly Media Web 2.0 Conference in late 2004.

He popularised the terms open source and Web 2.0.

Examples of Web 2.0 features include social networking sites and social media sites (e.g., Facebook), blogs, wikis, folksonomies ("tagging" keywords on websites and links), video sharing sites (e.g., YouTube), hosted services, Web applications ("apps"), collaborative consumption platforms, and mashup applications.

In the 2010s, the majority are interactive Web 2.0 websites, allowing visitors to leave online comments, and it is this interactivity that distinguishes them from other static websites.

Examples of Web 2.0 features include social networking sites and social media sites (e.g., Facebook), blogs, wikis, folksonomies ("tagging" keywords on websites and links), video sharing sites (e.g., YouTube), hosted services, Web applications ("apps"), collaborative consumption platforms, and mashup applications. Major features of Web 2.0 include social networking websites, self-publishing platforms (e.g., WordPress' easy-to-use blog and website creation tools), "tagging" (which enables users to label websites, videos or photos in some fashion), "like" buttons (which enable a user to indicate that they are pleased by online content), and social bookmarking.

In his book Digital Identities: Creating and Communicating the Online Self, Rob Cover argues that social networking's foundation in Web 2.0, high-speed networking shifts online representation to one which is both visual and relational to other people, complexifying the identity process for younger people and creating new forms of anxiety.

The term was invented by Darcy DiNucci in 1999 and popularized several years later by Tim O'Reilly and Dale Dougherty at the O'Reilly Media Web 2.0 Conference in late 2004.

The event was started by Tim O'Reilly, who is also widely credited with popularizing the term "Web 2.0".

Examples of Web 2.0 features include social networking sites and social media sites (e.g., Facebook), blogs, wikis, folksonomies ("tagging" keywords on websites and links), video sharing sites (e.g., YouTube), hosted services, Web applications ("apps"), collaborative consumption platforms, and mashup applications. A Web 2.0 website may allow users to interact and collaborate with each other in a social media dialogue as creators of user-generated content in a virtual community, in contrast to the first generation of Web 1.0-era websites where people were limited to the passive viewing of content.

Web 2.0, also called Participative (or Participatory) and Social Web, refers to World Wide Web websites that emphasize user-generated content, usability (ease of use, even by non-experts), participatory culture and interoperability (this means that a website can work well with other products, systems, and devices) for end users.

While the read-only goal was met, accessible authorship of web content took longer to mature, with the wiki concept, WebDAV, blogs, Web 2.0 and RSS/Atom.

Examples of Web 2.0 features include social networking sites and social media sites (e.g., Facebook), blogs, wikis, folksonomies ("tagging" keywords on websites and links), video sharing sites (e.g., YouTube), hosted services, Web applications ("apps"), collaborative consumption platforms, and mashup applications.

It has regained a new impetus through information technology, especially Web 2.0, mobile technology and social media.

Examples of Web 2.0 features include social networking sites and social media sites (e.g., Facebook), blogs, wikis, folksonomies ("tagging" keywords on websites and links), video sharing sites (e.g., YouTube), hosted services, Web applications ("apps"), collaborative consumption platforms, and mashup applications.

Mashups can be considered to have an active role in the evolution of social software and Web 2.0.

Major features of Web 2.0 include social networking websites, self-publishing platforms (e.g., WordPress' easy-to-use blog and website creation tools), "tagging" (which enables users to label websites, videos or photos in some fashion), "like" buttons (which enable a user to indicate that they are pleased by online content), and social bookmarking.

Tagging was popularized by websites associated with Web 2.0 and is an important feature of many Web 2.0 services.

A Web 2.0 website may allow users to interact and collaborate with each other in a social media dialogue as creators of user-generated content in a virtual community, in contrast to the first generation of Web 1.0-era websites where people were limited to the passive viewing of content.

Virtual communities may synthesize Web 2.0 technologies with the community, and therefore have been described as Community 2.0, although strong community bonds have been forged online since the early 1970s on timeshare systems like PLATO and later on Usenet.

Web 2.0, also called Participative (or Participatory) and Social Web, refers to World Wide Web websites that emphasize user-generated content, usability (ease of use, even by non-experts), participatory culture and interoperability (this means that a website can work well with other products, systems, and devices) for end users.

Libraries have had to undergo many changes in order to cope, including training existing librarians in Web 2.0 and database skills and hiring IT and software experts.

The term was invented by Darcy DiNucci in 1999 and popularized several years later by Tim O'Reilly and Dale Dougherty at the O'Reilly Media Web 2.0 Conference in late 2004.

Dougherty helped popularize the term "Web 2.0" at the O'Reilly Media Web 2.0 Conference in late 2004, though it was coined by Darcy DiNucci in 1999.

Personal web pages were common, consisting mainly of static pages hosted on ISP-run web servers, or on free web hosting services such as GeoCities.

With the rise of Web 2.0-style websites, both professional websites and user-created, amateur websites tended to contain interactive features, such as "clickable" links to online newspaper articles or favourite websites, the option to comment on content displayed on the website, the option to "tag" images, videos or links on the site, the option of "clicking" on an image to enlarge it or find out more information, the option of User participation for website guests to evaluate or review the pages, or even the option to create new user-generated content for others to see.

The popularity of Web 2.0 was acknowledged by 2006 TIME magazine Person of The Year (You).

The magazine set out to recognize the millions of people who anonymously contribute user-generated content to wikis and other websites such as Wikipedia, YouTube, MySpace, Facebook, and the multitudes of other websites featuring user contribution.

Web 2.0, also called Participative (or Participatory) and Social Web, refers to World Wide Web websites that emphasize user-generated content, usability (ease of use, even by non-experts), participatory culture and interoperability (this means that a website can work well with other products, systems, and devices) for end users.

Interactive sites are part of the Web 2.0 community of sites, and allow for interactivity between the site owner and site visitors or users.

Enterprise 2.0, PR 2.0, Classroom 2.0, Publishing 2.0, Medicine 2.0, Telco 2.0, Travel 2.0, Government 2.0, and even Porn 2.0.

Porn 2.0, named after "Web 2.0", refers to pornographic websites featuring user-generated content.

Enterprise 2.0, PR 2.0, Classroom 2.0, Publishing 2.0, Medicine 2.0, Telco 2.0, Travel 2.0, Government 2.0, and even Porn 2.0.

Enterprise social software (also known as or regarded as a major component of Enterprise 2.0), comprises social software as used in "enterprise" (business/commercial) contexts.

The popularity of the term Web 2.0, along with the increasing use of blogs, wikis, and social networking technologies, has led many in academia and business to append a flurry of 2.0's to existing concepts and fields of study, including Library 2.0, Social Work 2.0,

The concept of Library 2.0 borrows from that of Business 2.0 and Web 2.0 and follows some of the same underlying philosophies.

A third important part of Web 2.0 is the social web.

The social aspect of Web 2.0 communication has been to facilitate interaction between people with similar tastes.

Web 2.0 sites include the following features and techniques, referred to as the acronym SLATES by Andrew McAfee:

SLATES (Search, Links, Authorship, Tags, Extensions, Signalling) is an initialism that describes the business impacting capabilities, derived from the effective use of Web 2.0 technologies in and across enterprises.

In terms of Web 2.0's social impact, critics such as Andrew Keen argue that Web 2.0 has created a cult of digital narcissism and amateurism, which undermines the notion of expertise by allowing anybody, anywhere to share and place undue value upon their own opinions about any subject and post any kind of content, regardless of their actual talent, knowledge, credentials, biases or possible hidden agendas.

He is particularly known for his view that the current Internet culture and the Web 2.0 trend may be debasing culture, an opinion he shares with Jaron Lanier and Nicholas G. Carr among others.

All web applications, both traditional and Web 2.0, are operated by software running somewhere.

Servers often expose proprietary Application programming interfaces (API), but standard APIs (for example, for posting to a blog or notifying a blog update) have also come into use.

While "web API" historically virtually has been synonymous for web service, the recent trend (so-called Web 2.0) has been moving away from Simple Object Access Protocol (SOAP) based web services and service-oriented architecture (SOA) towards more direct representational state transfer (REST) style web resources and resource-oriented architecture (ROA).

The client-side (Web browser) technologies used in Web 2.0 development include Ajax and JavaScript frameworks.

While JavaScript, as first developed by Netscape (and later Mozilla), has long had a presence on the Web for many websites, it gained a particular pitch with the rise of the Web 2.0 era of computing, in which JavaScript became increasingly used for the development of user interfaces for applications, both web-based and desktop-based.