Just FYI, for those of you who are interested:
There's a compound called heme that is carried in your red blood cells. When the red blood cells die (a natural process), they are essentially broken down and the heme is released. So you gene "free" heme floating around. "Free" heme degraded to bilirubin. The intestine interacts with bilirubin to make stuff called urobilinogen, which is metabolized by bacteria and eventually makes stercobilins.
Stercobilins are brown. Hence, your intestines have a bunch of brown stuff in 'em. Hence, you poop and it is brown.
How's that for enrichment? HA!