Previously you used Google Analytics to track your account performance. According to Jeff, from the Google Analytics team-
As you may have found, Google Analytics can improve the performance of your account by helping you optimize your AdWords campaigns and showing you what aspects of your site are providing the most traffic and highest conversion rates.
Now, to help you reach your advertising goals with Google Analytics, we've started sharing information on feature enhancements and tips in our new blog.
So, if you already have a Google Analytics account, we hope you'll check it out. If you don't have an account and would like one, you can sign up here. As you may have heard, we're still in invitation mode, but it usually takes less than a week to send you an invitiation code.
You can find updates and tips on the recently launched Google Analytics blog.