[Intermernet]

From http://en.wikipedia.org/wiki/CUPS#History

"Michael Sweet, who owned Easy Software Products, started developing CUPS in 1997. The first public betas appeared in 1999.[3] The original design of CUPS used the LPD protocol, but due to limitations in LPD and vendor incompatibilities, the Internet Printing Protocol (IPP) was chosen instead. CUPS was quickly adopted as the default printing system for several Linux distributions, including Red Hat Linux.[citation needed] In March 2002, Apple Inc. adopted CUPS as the printing system for Mac OS X 10.2.[4] In February 2007, Apple Inc. hired chief developer Michael Sweet and purchased the CUPS source code"

CUPS is currently chiefly developed by Apple but, unlike many other commercially "owned" open-source projects, it has a license clause that exempts them from the license that applies to you and I.

I'm sure there are many other examples of this, I was originally pointing out that the licensing terms for WebKit and CUPS are not really that similar from Apple's perspective. From our perspective, yes, both GPL (well LGPL for WebKit)