Google Webmaster Central mentions the launch of their new feature – Message Center to their Google's Webmaster Console through which webmasters will receive messages.

Below is an example of the kind of information that could be sent to webmasters

The above example conveys the siteowner message about hidden text which is a forbidden as mentioned in webmaster guidelines. For more suggestions and changes, post at Webmaster Help Group.

Not just restricted to US Google Webmaster Central, the application is available to all supported Webmaster Tools languages (French, Italian, German, Spanish, Danish, Dutch, Swedish, Russian, Chinese-Simplified, Chinese-Traditional, Korean, Japanese, etc.).