Interesting post here: http://blog.telemapics.com/?p=245 on using OSM as an outsider
“For many of us, it seems so difficult to discover things about OSM, its data, and the use of the data. Maybe I just need to spend more time reading their Wiki (guilty). However, I admit that I am confused about OSM licensing practices and liability issues. Every time that I start to research these issues, I get a headache. While I think I understand the limitations of the license to use OSM data and why these “carve-outs” are necessary, I find it difficult to understand how to use the data to any commercial advantage and wonder if that will limit the usefulness of OSM’s contribution.”
Of course there is no confusion on using proprietary data – it’s very clear how expensive and wrong it is, and how they accept no liability.