I was recently looking at licenses for databases and discovered the ODbL license. This license was pioneered by the OpenStreetMap Project. I was reading their introduction to why the change was needed. This introduction outlined what the change was, what the change would allow them to do, who agreed, who disagreed, what the cost of the change would be, among other things. I thought it was a very open, engaging and confidence building way to move a group of volunteers through change. It allows for more kinds (also different kinds) of product use. It is well worth the look at not only if you are interested in the open licensing of data in databases and why CC-BY-SA and CC0 licenses do not work for data [also as PDF], but also how they are answering the questions of the community as they are moving the community through change.