[ryao]

People decided to listen to lawyers who read the licenses instead of listening to statements by people claiming to know how things work without actually reading either license or asking a lawyer about it. That is quite literally the only change.

[nailer]

Didn't Sun use lawyers to design the CDDL to precisely prevent this situation?

[e12e]

No, I've seen talks by the engineers behind Solaris (I don't recall who at the moment) that strongly indicated the Sun lawyers didn't go out of their way to be incompatible with the GPL -- they just wanted a license that allowed them to split proprietary and open code (as they didn't have the right to open up all of Solaris due to licensing agreements with third parties etc) -- and still being able to distribute both open and traditional closed Solaris. This led to the "per file" license nature of the CDDL -- and unfortunately to the "additional limitation"-bit that makes it incompatible with the GPL.

If it was done again today, they might have gone for the Apache license as I recall -- and avoided some of the unfortunate issues.