This technology changed the entire web technology native working environment and given web professionally to think and implement ideas besides worrying about the different platform.
Over the period of time we have invented or developed different web programming languages like Asp, JSp, PHP, ruby on rails, phython and etc. Different programming language demands different environment to sophistically develop apps that led to high technology gap between two apps developed in different platform. The data portability was almost impossible.
Then web2.0 was introduced to bridge the data communication gap between apps besides running on different platform.
With the help of web2.0 you can fetch the user data from a website through API. These days every single emerging platform provides the API (Application Programming Interface) for data sharing.
For example you might have seen a website that offers registering a new user account with facebook, twitter and gmail etc. accounts.
Web2.0 is not only limited up to registration purpose only but it is also helpful in different operation like flight ticketing, train reservation, mobile apps development etc.
If you have any doubt regarding web2.0 technology you can leave your doubt in below comment box, your comment is always precious for me. Thanks