Web 2.0 refers to web applications that facilitate interactive information sharing, user-centered design, and collaboration on the World Wide Web. Examples include social networking sites like Facebook and Twitter, video sharing sites, wikis, and blogs. Social networks consist of individuals or organizations connected by relationships. RSS allows users to subscribe to continually updated content from sites through a feed reader. APIs enable interaction and sharing of content between applications and sites. Widgets are embeddable applications that can turn personal content into dynamic web apps shared on websites.