To help you keep track of what’s new there are read and unread indicators.
When new content arrives you’ll see a green dot appear on folders:
The content you haven’t opened will have a bold headline like ‘So what is happening with the price of oil?’ below:
How to change ‘read’ content back to ‘unread’
Go into the article and click ‘More’ on the toolbar at the bottom of the screen and select ‘Mark unread’.