What is web 2.0 Technology and new added feature

Web 2.0 is a trend use in World Wide Web technology and web design.it is second generation of web-based communities and hosted services (such as social-networking sites, wikis and blogs) which aim to facilitate creativity, collaboration, and sharing between users.it includes a social element where users generate and distribute content, often with freedom to share and re-use. This can result in a rise in the economic value of the web to businesses, as users can perform more activities online.
web 2.0 techniques:
CSS to aid in the separation of presentation and content
Folksonomies (collaborative tagging, social classification, social indexing, and social tagging)
REST and/or XML.
Used Internet application techniques, often Ajax and Flash.
Semantically valid XHTML and HTML .
Syndication, aggregation and notification of data in RSS or Atom feeds .
merging content from different sources, client- and server-side .
Weblog-publishing tools .
wiki or forum software support user-generated content .
Internet privacy users to manage their own privacy in cloaking or deleting their own user content or profiles.
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.