On the iPad one should be able to view more contents in a glance. Now you have a series of screens with lists of folders and articles. It would be much better to have a sidebar that you can hide (depending on the device orientation) where you can select a folder or a tag, while the article view is always visible. Considering that these services are used for reasearch purposes by students, freelancers and so on, it’s important to make it more suitable and efficient for this kind of activity, where a global view is important