It's an incredible website! But it still does not work completely "right." For example, the back and forth buttons don't navigate to the correct scroll locations.

This actually illustrates his points. Which is this: the browser(s) ALREADY implement all of those features. It already knows forward and backward and new tabs and link and etc. etc. etc. SPA's completely ignore these and must re-implement everything. This means: * choppy differences between different SPA * when new browsers come out with new navigation features, guess what, you have to reimplement them! * Extra javascript code * Extra bug opportunities * What if a user keeps your page open so long that you change JSON? I have seen my wife keep a tab opened for weeks....

I guess this is just my DRY training kicks into overdrive, but reimplementation of well-tested, well-proven patterns really doesn't smell right. Which was his point.