Google also encourages the user to inform the webmaster if possible, although Google will attempt to inform the webmaster too provided he or she is signed up with its Webmaster Tools. Additionally, the search giant will attempt contact through any e-mail addresses featured on the cached, non-hacked version of the site.

The new feature is similar to the warning that appears alongside results that may contain malware (""), which has been in place for several years. This feature is also built into , whereby users are blocked from visiting the site, although it's not clear whether the hack alert will work in a similar way.

For obvious reasons, Google is keeping quiet about how it , but we have to hope it's not something as simple as the site contents changing in a sudden and dramatic way. After all, a simple site redesign can lead to this.

Additionally, any site with a forum might want to censor hacker terminology such as "pwned," in case Google is determining the hacked status via such keywords.

Google's also quiet about what a webmaster should do if he or she is the victim of a false positive. Such a mistake could seriously damage the reputation of a organization and even lead to a loss of business, especially if the site concerned is a retailer. I couldn't find any e-mail addresses for users to contact should this arise, and the only method for remedying the situation is to --as with malware warnings. There's no indication how long the review will take.