From a VentureBeat article about LinkedIn's "95 percent" HTML5 app:
"We did users studies in-house, and I don't think people noticed a big difference. Nobody said, 'Oh that's native,' or 'Oh, that’s web,'" said Prasad. "As long as we can make the experience fast enough, nobody can tell the difference. It still feels right."
A shining beacon of hope for the "everything is HTML" future. With a "full investment" in web technologies and avoidance of responsive design, LinkedIn nails the seemingly-native HTML5 app.