<http://schema.org/description>
"App.net, the social network that launched last year as a subscription-only and ad-free alternative to Twitter, will start accepting members who haven't paid a dime. It's an admission that, for internet startups seeking growth, nothing beats free. Starting today, annual members of App.net, who pay $36 a year, can invite some free users, whose accounts..."^^<http://www.w3.org/2001/XMLSchema#string>
<http://qz.com/56277/app-net-welcomes-non-paying-users-in-a-fresh-twist-on-freemium/>