Dear Webmaster Tools user,
We know that having a healthy and well-performing website is important to you. To keep you informed about your site's status Webmaster Tools will now automatically send you a notification email if there are critical or important issues that we detect with your site.
We'll only send you email for issues that we think have significant impact on your site's health or search performance which have clear actions that you can take to address. For example, we'll email you if we detect malware on your site or see a significant increase in errors while crawling your site.
For most sites these kinds of issues will occur rarely. If your site does happen to have an issue we cap the number of emails we send over a certain period of time to avoid flooding your inbox.
If you don't want to receive any email from Webmaster Tools you can change your email delivery preferences at https://www.google.com/webmasters/tools/preferences.
We hope that you find this change a useful way to stay up-to-date on critical and important issues regarding your site's health.
If you'd like more information about Webmaster Tools and building Google-friendly websites please visit http://www.google.com/webmasters.
The Webmaster Tools Team