Google AdWords team has found a solution to the most common problem in managing AdWords account -why your ad does not show for a particular keyword. The solution is a one-click feature that provides easy troubleshooting.
According to Peter H. from the Ads Diagnostic Tool team:
We're making the Ads Diagnostic Tool more accessible by incorporating it into the Ad Group details page. You can access this new feature via the new magnifying glass icon next to each keyword. If you are concerned that an ad is under-performing because of a particular keyword, you can point your cursor at the magnifying glass to get an instant diagnosis for that keyword. If the Ads Diagnostic Tool finds an issue that may be related to that keyword, you can receive troubleshooting suggestions by clicking the "What can I do now" link that appears inside the help bubble. If there are no issues with your keyword, the bubble will tell you that your ad is running normally on Google.com.
That's not all. Now you can request diagnostics for ads running in a specific geographic location. A direct link to the ad preview page for specific keywords has also been introduced. With competition from Yahoo! heating up and the test with newspapers underway, users can expect better service and better control on their campaigns in following days.
Viw the AdWords blog here.