<http://schema.org/description>
"When someone unsubscribes from your email list, it's hard not to take it personally. Opt-outs are inevitable, though, and the more you learn from them the fewer subscribers you're likely to lose in the future."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.businessknowhow.com/internet/optouts.htm>