Google said, "You're busy, and we know it's not always easy to stay on top of every innovation and change in AdWords." Adding, "to keep you informed about the latest and greatest, we wanted to share how we are making it easier to stay updated on important AdWords improvements and changes with the new look and feel on the Inside AdWords blog."
The first link, "major updates on our blog," is where you will find both in-depth posts on specific releases, as well as posts summarizing all the recent happenings in AdWords on a regular basis. Google specifically tags those blog posts with "Updates."
The second link, "all updates on Google+," features Google product and feature changes on the Google Ads Google+ page. Each post will be tagged with #adwords #updates to make them easily identifiable.
Forum discussion at Google+.