I'm about to launch a new version of my business's website today which incorporates the asynchronous UI concept while keeping SEO in mind.
I settled on building a JS-free version of the website using the templating system I've developed for the backend, and then loading in JS at the end of page load which replaces and rebuilds the site into an interactive UI for users with JS enabled.
Assuming Google doesn't try too hard to execute JS on the page, it should get a clean, "normal" version of the site, with all text & menus and everything else accessible, while users get something a little bit different (but with the same content).
We do the same thing. Our CMS delivers views based on the type of agent and whether JS is enabled or not. It allows our users who aren't able to handle all the fancy UI stuff (we have some blind users) to use the site without losing any functionality, much like Gmail static. With the proper design it's really simple to extend and add content this way.
I settled on building a JS-free version of the website using the templating system I've developed for the backend, and then loading in JS at the end of page load which replaces and rebuilds the site into an interactive UI for users with JS enabled.
Assuming Google doesn't try too hard to execute JS on the page, it should get a clean, "normal" version of the site, with all text & menus and everything else accessible, while users get something a little bit different (but with the same content).