Statuses is a microblogging module. Heartbeat displays a stream of user activity. Using Rules, you can integrate status updates into your Heartbeat activity stream.
Of the top 20 sites on Alexa, 11 are currently using the HTML 5 doctype. I didn't review which features of HTML 5 the sites have or have not implemented, simply what doctype they were using. Here are the current doctypes used by the top 20 sites on 1.22.12.