Ubiquity was a Mozilla Labs experiment that was in development from 2008 to 2009. Its purpose was to explore whether a radically different type of interface to the Web — a task-centric, natural-language-based command line — could help us get common Web tasks done faster.
Though the work on it is on an indefinite hiatus, the ubiquity extension for Firefox is available for download.
Factors which drove the project
Linguistic Interfaces- the need to make the interface close enough to their natural language that people can understand how to use it.
Task centric Web Browsing-the need to make the web task-ready rather than just a destination where one finds information
Ubiquity commands are small chunks of Java scripts which can interface with web services.
Wikipedia- One can get all the wiki pages of information by just typing the search topic
Map – one can get the Google map of his required destination to get the map right in front of his screen.
Email – the email command uses Gmail for now. One can email to friends using this add-on
Translate – Translates a phrase to any language you want.
The above four commands are some of the commands, you can read more about them at https:// wiki.mozilla.org/Labs/Ubiquity/Ubiquity_0.1_User_Tutorial
The project has been stopped as on Jan’2010 but Mozilla plans to revisit the project sometime in the future.
They have Google group/mailing list which is useful for command development, feature suggestion, and other high level discussions