Userscript license choice
Completely depends what you want to "protect" against. Creative Commons has a tool to help you pick one of theirs.
Thank you for your input. The problem with all the CC licenses is that they aren't designed for scripts and software, so they don't take into account concept like source code. I was more thinking of GPL, LGPL, MIT, Apache, BSD, WTFPL, etc...
I don't think lacking the concepts "source code" or "object code" is really a problem for an interpreted script, where the source code is what you distribute...
You can always pick one and change it later, if you're the only creator. It won't retroactively apply to old versions, of course.
For what it's worth: currently I use the BSD license, but with an added restriction that derivatives cannot @include Facebook (due to abuse on uso).
Userscript license choice
So I want to 'protect' my userscripts with a license. But there are so many with little differences.
I was wondering what license you have chosen and why...