[cheapsteak]

Having the URL exist on the server isn't the same as serving a rendered page from the URL, which is what most SPAs do. You could just rewrite all URLs in a website to point back to your index.html, then have the client side router initialize the app from the URL parameters. If you don't have javascript turned on (e.g. googlebot) then all you'll see is a blank page

[ricardobeat]

Googlebot interprets javascript. In that case you shouldn't use pushState but fragment URLs[1].

I should have said it is assumed that the URL exists on the server and points to the same resource/content; otherwise setting URLs using pushState makes no sense. GitHub is a good example of how it should be done, not an exception.

[1] https://developers.google.com/webmasters/ajax-crawling/docs/...