[wp-hackers] WordPress and GPLv3

Andy Skelton skeltoac at gmail.com
Fri Dec 28 21:33:39 GMT 2007

Thanks for clarifying.

On Dec 26, 2007 10:35 AM, Otto <otto at ottodestruct.com> wrote:
> And that is Tivoization. Wrapping the code into a black box that can't
> be modified.

This is an important issue for a lot of projects but I'm unable to
imagine this being an issue for WordPress. Do you have a use case in
mind here? Black-box personal web servers sold at a loss?

---- OT below this line ----

> I cannot protect my product and my business plan
> through technical measures. I cannot give away razors while trying to
> sell razor blades.

Yes, you can.

I did a little research on tivoization. Tivo can release their
products under GPLv3 and still protect their bottom line through
technical measures. The GPLv3 says:

"Access to a network may be denied when the modification itself
materially and adversely affects the operation of the network or
violates the rules and protocols for communication across the

So, under the GPLv3, the User Product may not refuse to run modified
code but if it relies upon a network and the software modifications
hurt the network (e.g. circumvent a payment system that is necessary
to the network's continued operation) the network may refuse access.
You can still do whatever you want with your Tivo hardware and they
can still build payments into their network service requirements. They
may not "brick" your device, but they may refuse access to /their
network/ for violation of any arbitrary rule, including unsigned
software. The only remaining problem is that they will not be able to
profit off people buying only the device and not the service. I expect
to see the GPLv3 Tivo priced much higher so as to profit on those who
do not buy service, with substantial discounts for long-term service
contracts just like cell phone service carriers.

The razor blade model works when the razor handle is truly useless
except for holding blades. As soon as your customer finds another
valuable use for the handle, your blade sales suffer and your revenue
model falls apart. That risk is much greater with a computer because
computers are more generally useful as a result of their intrinsic

GPLv3's User Product clause protects the rights of users to tinker
with their possessions. Simply put, it says you may not limit the
usefulness of a device. I believe that a device vendor that disables
modified devices is doing wrong and as a free software developer I
don't want my work to be used by any such vendor.


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