This is pretty cool but lower-tech than i was expecting when i saw the link. I went by their loft a few times in 2008 or 2009 but haven't followed them since. I think Makani is a sister company.
http://www.google.com/makani/about/
There's also other companies working on e.g. computerized winches that can react in hunderdths of a second, if I remember correctly
http://inhabitat.com/power-your-boat-with-kites-wind-power-b...