I found the article lacking in two respects:
1. It talks all around dedicated devices, but they never get their own bullet point. No general overivew of what ebook readers are out there (Kindle, Sony, many others) or why EInk is different from LCD.
2. "Each of the dedicated ebook readers supports exactly one DRMed ebook format." Is that really true? I thought some of the ebook readers that have been announced lately didn't. In any case that seems like a statement of a passing truth that's not really important; the point is your ebook reader only supports certain formats, and may or may not support DRM in those formats.