... when I think of projects I use every day which are programs I actually run (for example, as an artist I use Blender, Gimp and Inkscape regularly), most of these are under the GPL. How many truly major end-user-facing software applications can you think of that are under permissive licenses? I can think of many under copyleft, and very few under permissive licenses. This is no coincidence. Assuming you wish to fight for freedom of the end user, and ensure that your software remains free for that end user, copyleft is an excellent strategy. [...]