graeme_p - 8:33 am on Oct 5, 2010 (gmt 0)
@flood6, that is an entirely reasonable case for using this, because they are already know the platform. I just feel that this is being treated as more of a big deal than it is: it just means that there is one more open source CMS for that particular platform. Good, but hardly earth-shaking.
I think stuff like "open source is insecure" usually means "I do not want to learn anything new" or "nobody every got fired for buying Microsoft".
@ergophobe, I would word that as going from copyleft to "waived copyright". The next step from a BSD style license would be public domain (not common for software, but there are some examples around).
Regarding the obligations when writing exceptions, the first question is whether it is a derivative work: if you were writing the extension to a proprietary program would you need to check the license? If so, check the terms that apply to the open source one as well. Proprietary software may have contractual obligations as well, which complicates matters.
What the GPL allows can depend on architecture and method of distribution. GPL v2 says:
If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.
So you can do things like writing a GPL interface to your proprietary code. This is one section of the GPL that I find a bit unclear, and GPL v3 does not seems to have much narrower limits on this.