According to Google, “We are applying the power of Google machine learning to Newsstand’s rich catalog in order to find and recommend the most timely, relevant stories for you based on your individual interests. When you open the app, a personalized briefing shows you a blend of the top stories you need to know, including major headlines, local news, and personal interests. It’s perfect to start your morning, or to get caught up in under one minute during the day.”
Basically it seems that Google is making Newsstand more relevant to you by showing you topics that you are interested in. It will be completely personalized meaning that not everyone will get the same topics. Of course it won’t always be perfect, which is why Google will attach a justification to each recommendation, as well as giving users the opportunity to provide feedback so they know how to better the system.
The changes should already be live so if you are a Newsstand user, or if you just want to check it out for yourself, hit up its website for the details.