You test your idea on actual customers, you don't tell your idea to HackerNews. And even awesome companies like Facebook screw up when they test by running bad tests. Example: Home. Facebook tested Home on employees who usually use iPhones. Oops. If any of them read Robert Scoble or talked to a single Android fanboy, they'd realize Android is about customization. If a Nexus fanboy likes the Sulia widget or whatever you call it, said fanboy is not going to want to use Home when Home displaces Sulia.