web 2.0

• upload
• blogging
• social networking
• video sharing
• podcasting
• wiki
• online forums

Before web 2.0 internet user is limited to just download content on the web.
With web 2.0 internet user starts participating and sharing with webcams, digital music players,cell phones.
Web 2.0 enables user to express,interact and stay connected.

References:
http://www.youtube.com/watch?v=8iVj0upwymk

Web 2.0 describes World Wide Web sites that use technology beyond the static pages of earlier Web sites
Although Web 2.0 suggests a new version of the World Wide Web, it does not refer to an update to any technical specification, but rather to cumulative changes in the way Web pages are made and used.
A Web 2.0 site 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 Web sites where people are limited to the passive viewing of content.

Examples of Web 2.0 include social networking sites, blogs, wikis, folksonomies, video sharing sites, hosted services, Web applications, and mashups.

A mashup, in web development, is a web page, or web application, that uses content from more than one source to create a single new service displayed in a single graphical interface. For example, you could combine the addresses and photographs of your library branches with a Google map to create a map mashup

A wiki is usually a web application which allows people to add, modify, or delete content in collaboration with others.
Text is usually written using a simplified markup language or a rich-text editor.
While a wiki is a type of content management system, it differs from a blog or most other such systems in that the content is created without any defined owner or leader, and wikis have little implicit structure, allowing structure to emerge according to the needs of the users.

http://en.wikipedia.org/wiki/Web_2.0