What is Sugar?
Information is about nouns; learning is about verbs. The Sugar interface, in its departure from the desktop metaphor for computing, is the first serious attempt to create a user interface that is based on both cognitive and social constructivism: learners should engage in authentic exploration and collaboration. It is based on three very simple principles about what makes us human: (1) everyone is a teacher and a learner; (2) humans by their nature are social beings; and (3) humans by their nature are expressive. These are the pillars of a user experience for learning.
Sugar also considers two aphorisms: (1) you learn through doing, so if you want more learning you want more doing; and (2) love is a better master than duty—you want people to engage in things that are authentic to them, things that they love.
The presence of other people is always present in the Sugar interface: collaboration is a first-order experience. Students and teachers engage in a dialog with each other, support each other, critique each other, and share ideas.
Sugar is also discoverable: it can accommodate a wide variety of users, with different levels of skill in terms of reading, language, and different levels of experience with computing. It is easy to approach and yet it doesn't put an upper bound on personal expression; one can peel away layers and go deeper and deeper, with no restrictions.
Sugar is based on Python, an interpreted language, allowing the direct appropriation of ideas: in whatever realm the learner is exploring—music, browsing, reading, writing, programming, graphics, etc.—they are able to drill deeper; they are not going to hit a wall, since they can, at every level, engage in debugging both their personal expression and the very tools that they use for that expression.