This must be a gradual roll-out because I do not see it on mine yet.
Here is their blog on the new feature.
One of the easiest ways to boost your professional brand on LinkedIn is to find other like-minded professionals to connect and exchange ideas with in LinkedIn Groups. But with so many great conversations, up-to-date news and valuable information available, people often ask, “Where do I begin?” Today, we’re pleased to introduce a new destination designed to help you manage your participation in and discover LinkedIn Groups more efficiently and effectively.
To get started, simply select “Interests” from the menu at the top of your LinkedIn Homepage, then “Groups.” This new Groups landing page makes it easier to stay up-to-date on what’s happening in groups you manage or are a member of — making your time spent on LinkedIn and in LinkedIn Groups, more productive.
At the top of the page, you’ll see all of your current groups in one place. If the group has new activity, you’ll instantly see the number of updates, new discussions or job postings within that group when you hover over it. We’ve also made it possible to start or join a conversation in any of your groups directly from this page. New to groups? We’ll help you get started by suggesting relevant groups you can join today.
We’ve also added a new conversation feed to give you a quick peek at conversations that took place since your last visit, making it easy for you to quickly jump in.