The turning point that is HTML5; are you ready?

Data will be linked to other data, and the client based application will use it?

This sounds a lot like a general-purpose REST(ish) client. For instance, data comes back, with actions on that data tied to other URLs to request to. The client application will decide how to present it (is web design dead at this point?). This is interesting, as the client applications are literally data consumers - and the application developers really data architects. Its possible that there would be no web design, no HTML/CSS/Javascript, and another hollistic, more expressive technology will take its place.

Having data linked to other data is nothing we can't produce with well-designed web services today. Maybe there will be a JSON linked-data API standard. I could be getting the technology wrong but the concept is the same.

I'm not really sure how we would get away from presentation-focused web applications. The client would have to be fairly sophisticated to handle all of the different types of data structures coming in - and 'client data-browsers' would inevitably have different implementations (we'll still need the user agent string, won't we?). Add on top of that every application or 'view' will look the same as no design is added to it. Sounds boring and the masses probably won't catch on. I'm definitely missing something here, but the concept is fun to push around. Imagine how much larger/better/more sophisticated/faster our web applications would be if you only had to worry about data instead of also interface and state?

It doesn't really matter what comes - the mavericks and those willing to change (and not just progress) will jump on, and everyone else will be an outdated developer of yester-year. The concept is only scary to the lazy.

Sure HTML5 has some cool features (offline, canvas, location,etc.), but the benefit is simple: get fast beautiful desktop class applications inside of your browser so that you can use them anywhere without any IT headaches.

Considering that the HTML5 effort was originally called "Web Applications 1.0" I rather think he's missed the point.

HTML5 isn't (just) about rendering documents - it's a full application development technology.

I don't find his statement that "over-scripting" is another sign that the common Web browser is an out-dated product particularly compelling - in fact I don't even understand what it means.