Another interesting topic of discussion - importance of precise focusing. The article called "The Flawed State of Photography as Art and Documentation" talks about how even a slight shift of focus can change the expression of the person (subject of the photograph) and how hard is it to achieve. At this website there are a few more articles that explore the focusing issues in photography. The posted articels somewhat old and may not reflect the current situation, that's why you should take it with a bit of salt :). The articles are the following:

• A Calamity in the World of Art (Judging Artworks by Slide Reproductions)
• Why No Camera Can Focus
• Focusing Tests
• The Flaw in All Auto-Focusing Cameras: the Messraster Focal Point Exact Screen
• Why the Most Important Invention in Photography Is Not Available