jKeriamon, I basically agree with you, and think the notion of fecal matter building up for years is a little ludicrous - a lot of these places mention that "fiber abraisivly removes recent build up, but not fat build up and impacted fecal matter".
"As Dr James Balch writes, “Retained debris in the colon leads to the absorption of toxins resulting in systemic poisoning. Colon cleansing can rid the colon of debris and help prevent and treat a variety of health problems.”
In order to prevent such problems, it is recommended that one regularly cleanses their colon, small and large intestine. This is known as ‘colon cleansing.’ As the average adult has between 5 and 40 pounds of compacted waste in their bowels, a good colon cleanse would be of great benefit. It is important to know that all colon cleansing treatments are not equal, however."
and what about
the (warning, quite graphic) pictures athttp://tuberose.com/Colon_Health.html