Presentations are released under Creative Commons licenses that spell out exactly what may and may not be done with them; generally these are released under a ‘Creative Commons Attribution-Noncommercial-Share Alike 3.0’ License. This licence lets you remix, tweak, and build upon the work non-commercially, as long as you credit the author and licence your new creations under the identical terms. This means that any derivative works will also be non-commercial in nature. That is, you can use these materials flexibly but you can’t profit from them.
At the moment, many of the presentations I produce use the Yanone Kaffeesatz font, which is completely free – but not a standard font on most computers; so unless you install this font, the presentations will be a complete mess…
[Will be added here shortly]