What is Selenium WebDriver or Google WebDriver or Selenium 2.0?

WebDriver uses a different underlying framework from Selenium’s javascript Selenium-Core. It also provides an alternative API with functionality not supported in Selenium-RC. WebDriver does not depend on a javascript core embedded within the browser, therefore it is able to avoid some long-running Selenium limitations.
WebDriver’s goal is to provide an API that establishes
• A well-designed standard programming interface for web-app testing.
• Improved consistency between browsers.
• Additional functionality addressing testing problems not well-supported in Selenium 1.0.
The Selenium developers strive to continuously improve Selenium. Integrating WebDriver is another step in that process. The developers of Selenium and of WebDriver felt they could make significant gains for the Open Source testautomation community be combining forces and merging their ideas and technologies. Integrating WebDriver intoSelenium is the current result of those efforts.