Re: Mutopia copyright/legal issues

[Richard Stallman]

I basically agree with your ideas about free music licenses.

    * Pieces of music will often take inspiration from earlier music,
    sometimes even in direct ways. Say, playfully quoting a bar or two. 

This is considered "fair use", which means it is lawful regardless of
the license.  However, it is possible for the license to give a
broader permission-to-quote which extends the usual boundaries of fair
use.  For example, you could permit quoting up to 4 bars or 5 seconds
without any requirements.