"But the fatal flaw in the GPL is that the reciprocal clause is
only triggered by the act of redistribution. This works well in the
world of traditional software, where in order to use a program it
must be directly distributed to the recipient. Under the GPL, that
person then inherits the same rights to the software source code as
the distributor had. But now consider the strange new world of
cloud computing, and software as a service. The way software works
in this world is completely different. Most of the complex logic
and the actual programs themselves live as software only running
within server farms, communicating solely by network requests sent
from a client Web browser via downloaded Javascript programs.
"There is no "distribution" here, so the reciprocal clause of
the GPL is never triggered. In such a world, service providers can
use GPL-licensed code in proprietary back-end server farms with
impunity. This seems contrary to the spirit of the authors of much
of the GPL-licensed code used in this way, although it strictly
complies with the license. It means that, as Bradley warned, GPL
code can be used in the cloud computing market in exactly the same
way as BSD code can be used in the traditional software
market."