And therefore you can't mix GPL with AGPL; because if you move to AGPL you add additional requirements to the GPL'd code which is forbidden by the GPL.
The two licences are compatible, so people can make this decision without creating any legal barriers to sharing or collaboration.Huh? Can I take code from an non-free/AGPL'd web app and put it into a free/GPL'd web app without having to move to AGPL? I doubt it.
I think AGPL is nuts, worse the the GFDL mess.The AGPL seems to give an escape route from free/GPL to non-free software that wasn't present with GPLv2/AGPLv2, killing one of GNU GPL's unique selling points.