Having spoken with the developer, it transpires that there are no links and no exhortations to make purchases within the app. The cause of the rejection is a static-text label (in other words not a link) on the login screen…Just information. Nothing about payments, costs, or anything else. Just a small sentence so that people who download the app don’t immediately go “muh-huh?” After all, there’s not really any other indication in the app that it’s part of a web service, and we know that an awful lot of shoppers don’t read the app store blurb on the apps they download.
Readability’s response is to “go the other way…towards the web.” In this case, that’s their choice, but with a third-party client for another service (Dropbox, say) the app developer might not have the option of supporting in-app purchase. I don’t think people realize how many apps and services this could potentially affect. In theory, this means that even though Instapaper subscriptions don’t (yet) affect the app’s operation, the app will have to be re-engineered to support in-app purchase and give Apple a cut. Also consider that Readability provides some services for free, and yet because they also offer subscriptions, they will not be able to provide the free services in an app. This could apply to Dropbox, too. If storing and displaying your Web bookmarks is considered providing content, surely storing and displaying your files is, too.
I also liked this paragraph from a different post by Dovey:
When I purchase books from Apple’s iBookstore, they are providing a new service to me—the assembly and provision of an eBook. When I purchase one from Amazon or Kobo, Apple is providing no such service to me whatsoever. The argument that they have the right to claim some money because I’m using an Apple device is false, because I’ve already paid for that device—upwards of $700 in this case. I don’t get charged by Apple when I browse the internet or watch YouTube, so why does Apple need to take a cut when I download an eBook?