More than that, it allows any recipient to redistribute. You can buy one copy for $10 and immediately give it to everyone else.

That's what I mean by "should be able to do with it whatever you want" :)

This is going off-topic, but I'm curious. Does this mean I can take a GPL project, modify it, then sell the binaries+source for $$$ and refuse to release my modifications for free?

Yes, as long as you make the source available to customers under a GPL-compatible license (i.e. with no restrictions on their modification or distribution), you can charge whatever you like.

Though it only takes a single buyer publishing your changes to potentially undermine such a business model.

I think Red Hat’s approach is that they will refuse to sell you any more versions if you do that. I’m not sure if I like it or not.

Not sure how they'd enforce that since you can republish anonymously. Also not sure how the various CentOS alternatives that have popped up in recent years would work in that case, they'd need to find a new person to buy it every time there's an update.

With CentOS, Red Hat pulled a cunning move: they started supporting the project themselves, then after some time changed its direction from a repackaged white-box Red Hat to a fast-moving prerelease Red Hat. Now it's much harder for a bigger business to decide which of the CentOS-lookalikes to choose.

Your modifications will be GPL licensed so you still need to provide the source code for your modifications.

Roughly speaking, with GPL binaries can cost someone money but source code is always free of charge.

> You are required to contribute patches of your modifications back to the upstream project

That is not required by the GPL, you only have to distribute source to people you distribute binaries to. Those people can decide to redistribute it (or not) to anyone (including upstream) of course, and they are bound by the same terms as you are.

Yeah, edited.