It didn't work because Google didn't create it as a strong signal. Make it matter and the majority of sites will change the next time. One Tweet from Matt Cutts

It didn't work because Google didn't create it as a strong signal. Make it matter and the majority of sites will change the next time. One Tweet from Matt Cutts and everyone's already re-doing sites for SEO purposes. Set clear guidelines and rest will follow. But Google wants to build its own news portal to compete with FB.