The move is important. According to most accounts, Cox was second only to Linus Torvalds in the early Linux days, working on the kernel from version 0.11, and sorting out the networking. In the last ten years, he's helped Red Hat establish Linux as a commercial operating system, and become an advocate in debates on patents, privacy and civil liberties.
So what does the move mean? Possibly two things.
1. Red Hat doesn't need so much low-level coding work. It's going "up the stack", according to Matt Asay at CNET, and creating "partner ecosystems" and "value-driven IT solutions" which are "about as far from hacking kernel code as you can get", according to Glyn Moody at Computerworld UK. Moving to a hardware company, where those issues are central will be "good news both for Cox and for the free software world", says Moody.
2. It might just be a sign of Intel turning on Microsoft. "Intel has been very quietly developing itself into a Linux powerhouse," says Charlie Dermerjian at The Inquirer.
What if Intel decided to stick the boot in Microsoft, just when it's wringing its hands over the PR disaster that is Windows Vista and Windows 7?
It's an interesting thought - though low-level kernel skills won't be so crucial as the user interface, if Intel really does decide to back Linux against Windows.
Enjoyable as the speculation might be, it's a million miles from Alan Cox himself, of course. From the tone of his excellent, brisk announcement, it's clear he will be getting on with what he does best, in his usual good-humored fashion.
Here it is in full:
Subject: Moving on from Red Hat
I will be departing Red Hat mid January having handed in my notice. I'm not going to be spending more time with the family, gardening or other such wondrous things. I'm leaving on good terms and strongly supporting the work Red Hat is doing. I've been at Red Hat for ten years as contractor and employee and now have an opportunity to get even closer to the low level stuff that interests me most. Barring last minute glitches I shall be relocating to Intel (logically at least, physically I'm not going anywhere) and still be working on Linux and free software stuff.
I know some people will wonder what it means for Red Hat engineering. Red Hat has a solid, world class, engineering team and my departure will have no effect on their ability to deliver.
Alan  I note that both the family and garden probably think I should