Definition of Web 2.0: Web 2.0, a phrase popularized by the first Web 2.0 conference in 2004, refers to a perceived second generation of web-based communities and hosted services — such as social-networking sites, wikis and folksonomies — which facilitate collaboration and sharing between users. O’Reilly Media titled a series of conferences around the phrase, and it has since become widely adopted. Although the term suggests a new version of the World Wide Web, it does not refer to an update to Web technical specifications, but to changes in the ways software developers and end-users use the web as a platform. According to Tim O’Reilly, “Web 2.0 is the business revolution in the computer industry caused by the move to the internet as platform, and an attempt to understand the rules for success on that new platform.” Some technology experts, notably Tim Berners-Lee, have questioned whether one can use the term in a meaningful way, since many of the technology components of “Web 2.0″ have existed since the early days of the Web.

Definition of Travel 2.0: Travel 2.0, a phrase coined by PhoCusWright Inc. is an offshoot of the Web 2.0 phenomenon. Like many other industries, the online travel industry is currently in transition, adapting to new technologies and trends available on the Internet. Travelers, for their part, are becoming increasingly more interested in finding the opinions and reviews of their fellow travelers in lieu of professional travel advice. This impact is significant given the travel sector’s economic influence on the Internet, indeed more money is spent on travel than anything else online. Roughly two-thirds of Americans research and plan travel online and approximately the same amount book online as well. The online travel industry breaks down into several different categories: online travel agents, online travel guides, online travel planners, and online travel communities and forums. Together, these four groups make up the bulk of what are considered Travel 2.0 companies.

Travel 2.0 is a term that represents the extension and customization of the concept of Web 2.0 into a form that applies to the world’s largest industry: travel and tourism. It defines a transformation of online offerings into a new level of user empowerment and functionality. More than “Move to the Internet” as a platform, though, it is about how business forces that characterized Web 1.0 are yielding power, influence and eyeballs to the socially oriented Web 2.0. For Web 2.0, Tim O’Reilly described the following new models or different approaches that illustrated the divide between 2.0 and 1.0.

Definitions from Wikipedia (more about Web 2.0 and Travel 2.0)