“ Habit #2 Continuously extending a conversation. (read full comment) ” 

Posted on June 15, 2010 at 8:03 AM EDT

“ To produce food in the US, we use 94 million acres of farmland. My back of the napkin calculation says it takes .35 b bushels of corn /billion... (read full comment) ” 

Posted on July 16, 2009 at 11:44 AM EDT

“ Credit due to South American Indians Charles C. Mann's book, "1491" describes how South American Indians used controlled burning to enrich the... (read full comment) ” 

Posted on April 26, 2007 at 7:46 AM EDT