In this video, Linus Torvalds explains the GPL v2, v3 and BSD licences in very simple terms : http://youtu.be/PaKIZ7gJlRU
A management summary:
BSD Here’s some stuff we wrote. You can use it however you like.
GPL 2 Here’s some stuff we wrote. You can use it but if you make any improvements you have to give them back to the authors if they want them. (Linus likes this one)
GPL 3 Here’s some stuff we wrote. You can use it but anything which uses it or is derived from it, also has to be given away free. (Linus believes this is good for software freedom but not for personal freedom. Richard M. Stallman like this one.)
Sorry there was no pie-chart or smiley-faces. A smiley Linus vs a smiley RMS didn’t seem fair.