Creating an all-purpose REST API for Cloud services using Apache Felix and Sling

Let's say you need to provide an internet service to your users. Chances are that your service should be available via REST. Let's say your service should both provide data to users as well as accept data posted by users, and possibly some logic. Now let's assume your service turns out to become incredibly popular, with lots and lots of users. Sounds like you need Apache Sling and Felix in the cloud.