Why was the MIT license chosen for Bitcoin?
Satoshi:


  If the only library is closed source, then there's a project to make
  an open source one.
  
  If the only library is GPL, then there's a project to make a non-GPL
  one.
  
  If the best library is MIT, Boost, new-BSD or public domain, then we
  can stop re-writing it.
  
  I don't question that GPL is a good license for operating systems,
  especially since non-GPL code is allowed to interface with the OS. 
  For smaller projects, I think the fear of a closed-source takeover is
  overdone.