So I've got an idea for an app that will allow providers, like Tumblr, to provide content on iPhones without their service being constrained by Apple's whims about what can and can't be done by an app on one of their phones.
Basically, the app acts as a generic presentation platform, that the phone user can use to request content from the provider's servers. The provider, in response to such requests, can send back content and a description of how it is to be displayed, and also instructions describing how the various bits of the content relate to each other, allowing the provider to customise navigation of the content according to their needs.
The provider is then able to serve content to any iPhone user without first requiring the user to install an Apple-approved app first.
Okay, since my app is so generic, a user may have to do a little more to get content from a specific provider (namely, tell the app which provider to request content from), but I'll provide a mechanism where the user can ask the app to record such a request for later use, and to include an icon for it on the app's start screen. Once that's done, using my app as a way to access the provider's content becomes a matter of two taps. Which is only one tap more than a dedicated app would require, so I think it's a fair tradeoff.
While I'm about it I might as well make an Android version as well.