The GPL does _NOT_ prevent redistribution, please don't spread more incorrect information. It prevents _redistribution without redistribution of source_. You're still free to get GPL code, change it yourself, and never release it again.
Licenses like the AGPL were created in part because of this problem; some folks think that, morally speaking, code running on a server behaves like distributed code, and should be available. But for example: you're absolutely allowed to take GPL code, change it yourself, keep the source private, and run a web 2.0 business on top of that source code.
Where in my message did I say it prevented redistribution ? Can you quote the sentence that made you understand that ? (this is a serious question)
It's not what I meant, and I don't thing it's what I've written either. If anything, it actually forces redistribution in case some might not want to (when you release a binary but want the sources to remain yours).
Licenses like the AGPL were created in part because of this problem; some folks think that, morally speaking, code running on a server behaves like distributed code, and should be available. But for example: you're absolutely allowed to take GPL code, change it yourself, keep the source private, and run a web 2.0 business on top of that source code.