<http://schema.org/about>
"Earth Hour has teamed up with Zerofootprint to provide two carbon calculators that enable Earth Hour participants to measure their carbon footprint. Measure yours at http://earthhour.zerofootprint.net/. Or try the Facebook version that will allow you"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/corporate-responsibility/zerofootprint-and-earth-hour-have-teamed-up.html>