[untog]

I covered it very briefly in the post, but could/should have gone into more detail. You can store all of your static HTML/CSS/JS on an S3 instance, then have a separate EC2 (or whatever) to do the database stuff.

Create it as an API that's reachable through JSONP or (better) CORS. It won't stop you having scaling issues, but it'll help to reduce the number of requests hammering your database. I've recently spent an unhealthy amount of time setting up Varnish to cache dynamic content, so a post on that topic will be coming down the pipeline soon.