The Great American Soap Overdose, by The Wall Street Journal. Yuch. This article was very interesting and beneficial, and also includes a neat interactive illustration (which they also printed) by Jason Schneider.
Be sure to read the comments! One guy mentioned how in Europe, when the efficiency washers first came out, they told everyone there was enough soap residue in their clothes that they didn't need to add any to their laundry loads the first couple washes. ich.
