Google Wave

                         Google Wave is "a personal communication and collaboration tool" announced by Google at the Google I/O conference on May 27, 2009.Initially released only to developers, a "preview release" of Google Wave was extended to nearly 1 million users beginning September 30, 2009, with the initial 100,000 users each allowed to invite from twenty to thirty additional users.
 
             Google Wave is designed as a new Internet communications platform. It is written in Java using OpenJDK and its web interface uses the Google Web Toolkit. Google Wave works like previous messaging systems like email and Usenet, but instead of sending a message along with its entire thread of previous messages, or requiring all responses to be stored in each user's inbox for context, message documents (referred to as waves) that contain complete threads of multimedia messages (blips) are perpetually stored on a central server. Waves are shared with collaborators who can be added to or removed from the wave at any point during a wave's existence.

API

Google is building APIs that allow developers to use and build on Google Wave by way of:

• Extensions, program robots to automate common tasks and/or build gadgets to extend or change user interaction (e.g., posting blips on microblog feeds or providing RSVP recording mechanisms).
• Embed, dropping interactive windows into a given wave on external site, blogs, etc

Google released a Loooooooooong video for its Wave Preview which was recorded at the Google`s Wave Developer I/O Conference. Its said to be the first long video telecast over you-tube for preview purpose.