There are many ways to contribute to opensource software (OSS), programming only being one of them. I develop OSS, but use OSS too. For example, I am a big user of the Linux kernel, the KDE desktop, Kubuntu, Debian (I have unstable in a chroot), Firefox, Eclipse, Classpath, and many, many others. What these have in common, is that I generally have no time to look into the source code of these projects.