You can zoom article depending on your interest level in a topic ! You're getting different variants of text depending on the zoom level. At higher zoom levels different aspects of the story are unfolding. It is giving flexibility as reader may pick variant depending on his interest level and free time.
Some articles require that you have some previous knowledge. Users should be introduced but long introductions aren't good for more savvy readers. In our app user may tap "I don't understand" button and answer couple of questions to check his knowledge. Depending on results he will be offered shorter or longer introduction. Different questions and explanations depending on the answers can be edit in resource files.
3. You can also write pieces of texts that are going to be displayed only for the users staying in particular area. So for instance when covering Eastern Ukraine conflict, you can have fragments visible only for readers from neighboring countries. When you're writing about new iPhone release you may modify text to say if inhabitans of some country have it already available.