New Twitter is really the example to look at here (and they aren't the first). New Twitter doesn't have unique pages anymore for tweets, and everything is happe

New Twitter is really the example to look at here (and they aren't the first). New Twitter doesn't have unique pages anymore for tweets, and everything is happening in a single page. But each of those tweets also has a real HTML version generated separately for SEO. That is a perfectly valid way to do it, especially when you think of New Twitter as a content creation app, and each individual tweet as its own random piece of content. Granted, the simplicity of Twitter's content makes that choice easier than it might be for a lot of people, and I agree that hopefully we'll converge on tools and frameworks that will make this more automatic. But in a world where your app is largely running on the client, and data exchange is done largely via some kind of simple REST AJAX API, writing an additional (likely quite simple) HTML template for the same data doesn't seem like an impossible challenge for most web apps.