Ubiquity is an extensible command line interface built into Firefox that allows users to search the web, tag pages, and edit pages directly from the browser. Commands can be created by third-party developers to add additional functionality like analyzing page links or integrating with project management systems. The document discusses installing additional commands, the resources and libraries available for command development, and provides an example command for adding "nofollow" tags to page links. It also outlines some ideas and caveats for the continued development of Ubiquity.

1. Hacking Ubiquity Presented by Andy Edmonds http://surfmind.com