In the article you write:
If you have Ogg Vorbis files that you want to add to your DJ playlist, you can do so with a couple of minor adjustments. First, I recommend that you download the OggVorbis.component from the QuickTime Components Project. I've tested this component with QT 6.1.1, and it works great. Add the component to your QuickTime Library (System/Library/QuickTime), then launch the QT Player. ...
Isn't the /System/Library for Apple's OS use? I believe non-OS items are best managed by Apple (ie. the OS Software Update tool) and the user/owner when placed in either the /Library or /Users/<username>/Library, depending on system-wide vs. user-specific scope. All three 'library' folders/directories are different, and are intended to serve different purposes.
This is not a matter of having the Ogg Vorbis component work or not. Its a matter of creating potential future problems by providing poor advice, or NOT.
Someone in-the-know should straighten this out.