<http://schema.org/about>
"It is impossible to write anything about offsetting these days without prompting a flurry of responses that point out its problems and pitfalls. Travel offsetting just encourages people to fly more, critics complain. Or energy emissions offsetting does"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/sustainable-product-design/zerofootprint-designing-away-the-problems-of-offsetting.html>