Opening the box meta-level interfaces needs and solutions

This paper begins by considering reasons why some form of meta-level interface may be required for modifying or exploring existing user interfaces, from obvious functional reasons of customisation and personalisation to more political and social goals such as education and empowerment. The paper considers examples of systems developed by the author and others, and uses these to present a number of techniques and principles for effective meta-interactions. Some of these concern more surface manipulation, and others deeper levels of code and metadescriptions of the application and UI. It concludes that meta-interaction may be a key element for future liberal society.