It's difficult to generalise his work, so this is a reasonable summary. He seems to write about subjects he thinks are important to society - covering topics such as copyright, DRM.

I'd agree that with others here that he is an excellent writer, and his piece on 'the war on general purpose computing' is something which stands out in my mind as one of the most profound pieces I've read in tech.

EDIT: I think this is the article I had in mind [1]

[1] https://boingboing.net/2012/01/10/lockdown.html