Don’t panic! Don’t panic!
There’s a good chance that your site has not been hacked. However, if in the future, your web site were to suffer at the hands of some malicious hacker, Google Webmaster Central will alert you to that fact.
Starting this month, we will notify more webmasters of more potential issues we’ve detected on their websites, including:Starting this month, we will notify more webmasters of more potential issues we’ve detected on their websites, including:These notifications are meant to alert webmasters of potential issues and provide next steps on how to get their sites fixed and back into Google’s search results. If it pertains to a hacking or abuse issue, the notification will point to example URLs exhibiting this type of behavior. These notifications will run in parallel with our existing malware notifications.
The notice will look something like this:
Google also suggests that it is considering these alerts to include "other types of vulnerabilities or abuse issues." What that means, who knows? I know you shouldn’t hold your breath that Google’s going to tell you how to improve you rankings any time soon.