You should definitely have a look at existing data licences to start with.
http://opendefinition.org/guide/data/
http://opendefinition.org/licenses/
I take your point about commerciality, but that's just fraught with problems; we may all agree we don't want an evil corporation making megabucks from data we don't have a chance to control, but what about an educator in a university charging fees for tuition - can they use our data? Demanding non-commercial use can end up blocking 'good' use down the line.
Posted by Laura James at July 7, 2012 08:09 PM