The Adobe flash plug-in is non-free software, and people should not install it, or suggest installing it, or even tell people it exists.

Proprietary software tends to have malicious features. The point is with a proprietary program, when the users dont have the source code, we can never tell. So you must consider every proprietary program as potential malware.

I have met bright students in computer science who have never seen the source code of a large program. They may be good at writing small programs, but they can't begin to learn the different skills of writing large ones if they can't see how others have done it.

I figure that since proprietary software developers use copyright to stop us from sharing, we cooperators can use copyright to give other cooperators an advantage of their own: they can use our code.

I could have made money this way, and perhaps amused myself writing code. But I knew that at the end of my career, I would look back on years of building walls to divide people, and feel I had spent my life making the world a worse place.

The most powerful programming language is Lisp. If you don't know Lisp (or its variant, Scheme), you don't appreciate what a powerful language is. Once you learn Lisp you will see what is missing in most other languages.

Anything that prevents you from being friendly, a good neighbour, is a terror tactic.