The Value of the Public Domain

More light reading - this time about the public domain. Or rather, a little beyond the traditional public domain, as the author Rufus Pollock states:

Traditionally, the public domain has been defined as the set of intellectual works that can be copied, used and reused without restriction of any kind. For the purposes of this essay I wish to widen this a little and make the public domain synonymous with ‘open’ knowledge, that is, all ideas and information that can be freely used, redistributed and reused. The word ‘freely’ must be loosely interpreted – for example the requirement of attribution or even that derivative works be re-shared, does not render a work unfree.

It's quite academic in tone, but has some useful references (even if it misses out a crucial one - not that I'm bitter...).