I started hacking on code that I want to publish soon, so I read enough to get a simple introduction to the various free software licences. The GPL v2 and v3 and apache licenses all seemed needlessly complicated. The MIT and BSD licences were nice and short, and very similar. Someone else noticed the similarities and merged those two to the ISC license, which is what I am settling for now. It is very permissible (read: not copyleft).

The choice was influenced by The Failure of the GPL, which examines a particular case which looked like a win for the GPL but in the author's opinion was not. My inner pragmatist and idealist were arguing over copyleft, but changes in how I act ( favoring simplicity and faith in the natural order of things) meant the idealist won. One downside to the ISC is that it does not enforce anyone using my code to show me any improvements they make on it. The other downside is that it falls under the OSI category of 'Licenses that are redundant with more popular licenses', but it's so simple that if anyone wanted to use my code could do so easily.