Add simular items like in news.google.com? Polling many feeds is going to have many of the same items.
Use an algorithm in the reader to group same news items from different sites. it would allow the reader to showcase an item along with different perspectives on that item. Like CNN may talk about the 2015 elections when they happen and so would the NY Times. Grouped together I could read CNN and jump to NY Times right below with searching all my feeds for the same type of items.