Google Wave

Google Wave is an online tool for real-time communication and collaboration. A wave can be both a conversation and a document where people can discuss and work together using richly formatted text, photos, videos, maps and more. It was announced by Google at the Google I/O conference on May 27, 2009. It is a web-based service, computing platform, and communications protocol designed to merge e-mail, instant messaging, wiki, and social networking. It has a strong collaborative and real-time focus supported by extensions that can provide, for example, robust spelling/grammar checking, automated translation between 40 languages, and numerous other extensions.
Google Wave is designed as the next generation of Internet communication. It is written in Java using OpenJDK and its web interface uses the Google Web Toolkit. Google plans to release most of the source code as open source, allowing the public to develop it features through extensions.