Defining open data

Peter Murray-Rust, Open Data - the time has come, A Scientist and the Web, September 12, 2006.  Excerpt:

The term "Open Data" is now becoming commonly used and we (Blue Obelisk) are trying to define it (our mantra being ODOSOS. Open Data, Open Source, Open Standards). It was not commonly used two years ago although the concept is general enough to have been important. In the last 12-15 months there has been a lot of use, particularly in the techie web logs and meetings. The idea is potentially very much broader and looks set to become very important....

There seem to be several related threads:

• scientific data deemed to belong to the commons (e.g. the human genome)
• infrastructural data essential for scientific endeavour (e.g. GIS)
• data published in scientific articles which are factual and therefore not copyrightable
• data as opposed to software and therefore not covered by OS licenses and potentially capable of being misappropriated. (this is a very general idea)

I think the current usages are sufficiently close that we should try to bring them together. Comments here would be useful. Maybe a Wikipedia article would help?