Earning money with FOSS (a quick sum-up)

Bart K. wrote some thoughts about how to make money with FOSS:
http://freegamer.blogspot.com/2011/06/some-thoughts-on-commercial-foss-game.html
and Modplanman a bit more here: http://ubuntuforums.org/showthread.php?t=1442535

Just to have a quick sum up of these two. Read them for details and so on.

1. Code and assets closed
2. (a)Open code and closed assets Or (b) closed code and open assets
3. Open code and assets