My Personal Journey from MIT to GPL

It satisfies the four essential freedoms guaranteed of free software:

The MIT license basically allows you to do whatever you want with the software. The collective effort of the free software community amounts to tens of millions of hours of work, which you can download at touch of a button, for free. The GPL is the legal embodiment of this Golden Rule: in exchange for benefiting from my hard work, you just have to extend me the same courtesy.

Source: drewdevault.com