I was always impressed with Jacques Vallee’s thinking on the UFO business; and he has written about this, too. What he says seems important in ways that go beyond ‘crop circles’:
http://boingboing.net/2010/03/23/in-search-of-alien-g.html#previouspost
http://boingboing.net/2010/04/08/crop-circles-part-de.html#previouspost
http://boingboing.net/2010/04/28/of-flattened-flora-a.html
http://boingboing.net/2010/06/21/of-crop-circles-meme.html
Interesting info at the links. Thanks.