I've just been reading a thread on Googles Webmaster Central Blog, about how they are improving notifying site owners of "badware" that they think they have identified on a site.

Not only is there a section of the Google Webmaster Tools that will tell you what they perceive as "badware", they will also email you to notify you about this.

The difficulty with this system, is how do they identify the email address for the site, as it is not always clear?

The full thread can be found at http://googlewebmastercentral.blogspot.com/2007/02/better-badware-notifications-for.html