Web 2.0 includes websites that exhibit some of the following characteristics:
The web site can deliver an application such as a video player, a word processor program or music player for example. The applications are embedded in the site and run online. In many cases, you do not need to install anything on your computer to run the applications from the website.
USER GENERATED CONTENT
Users can edit, manipulate or own the content they post to a site. The content is commonly in the form of videos, images and text.
User participation adds to the content of the website. This can be in the form of publishing user content or adding reviews of posted content. Even commercial sites like eBay or Amazon have a high level of user participation in the reviews of products and sellers.
An easy to use interface can make the difference for a web 2.0 site. If it is difficult to understand or hard to create content on a site, users will be less likely to use and recommend it to others.
Social Networking sites allow users to connect with other users. Some sites are purely social allowing users to connect with friends however, social networking sites can also create networks based on a particular theme. Social Bookmarking sites allow users to share their favorite links.