Missleading and Missing the Point
The article is misleading and most of the comments are missing the point. The OEM activation of Windows 7 is a minor evolution of the OEM activation of Vista. (Note that the OEM activation of Vista was itself an evolution of the OEM XP activation.)
First, the reason for OEM activation: the OEMs did not want to inconvenience their customers with the hassle of needing to activate their new computers, so they worked with Microsoft to create a system where the OS would be automatically activated if it met certain conditions.
These conditions in Vista/7 are:
1. A specific code in the BIOS of the machine that identifies it as coming from an approved OEM (Dell, HP, Asus, etc). This is called the SLIC table.
2. A corresponding certificate must be installed in the OS. The BIOS table and the software certificate (an xml file actually) must "match up" - i.e. be from the same OEM.
3. A corresponding serial number.
If a machine has all three, then it is automatically activated. The article is misleads in that it implies that all that is necessary if the "master key" to activate any Windows 7 installation while the reality is that the key is only one of three components of OEM activation.
Going off the inaccurate information in the article many are jumping to the conclusion that Microsoft will/should revoke the key. I'll try to explain why this won't happen but for this we need to dig a little deeper into how Vista OEM activation works. Since Windows 7 OEM activation is only a very minor evolution over Vista's, this will shed light on how I assume it will work in Windows 7.
To facilitate the Vista OEM activations on their PCs, every OEM is provided with a unique BIOS SLIC table and a unique certificate file. The OEM keys are where things got interesting; the OEMs were each provided with several unique keys for the Home Basic, Home Premium, and Business editions of Vista as those were the versions that they would be selling the most of. Since the OEMs only very rarely installed the Ultimate edition on their PCs, only one key was provided for all OEMs to share . This could be considered the "master key".
The reason I think that this "leak" won't matter is that it would have happened when OEMs started shipping Windows 7 PCs in October. That is exactly what happened with Vista; just this time around people knew what to expect.
There exist multiple free tools online that will extract your Windows key for you; same for extracting an OEM certificate from a OEM activated Windows install. That yields 2 of the 3 needed components. The hard part is getting the necessary SLIC table into your BIOS.
This was accomplished by one of two methods: by having software emulate the necessary BIOS or by embedding the SLIC table into the native BIOS. The first method was quickly discovered and disabled by Microsoft while the second is virtually impossible to detect - but is more risky as you run the risk of bricking your hardware with either a bad BIOS flash or an improperly modified BIOS.
For these reasons I believe that Microsoft will not be changing the "master key" but will continue to crack down on the software BIOS emulation schemes.