If the search giant believes a site has been hacked, your search result will have the sentence "this site may be compromised" below it.
Google users will find the warning to be very similar to what the company already uses for sites that spread malware.
Says Google of the update (via eW):
"We've provided notices for malware for years, which also involve a separate warning page. Now we're expanding the search results notifications to help people avoid sites that may have been compromised and altered by a third party, typically for spam. When a user visits a site, we want her to be confident the information on that site comes from the original publisher."
If you click on the warning, more information is available about the site. If you still want to visit the site despite the alert, you can click-through.
Concludes the search giant:
"We use a variety of automated tools to detect common signs of a hacked site as quickly as possible. When we detect something suspicious, we'll add the notification to our search results. We'll also do our best to contact the site's webmaster via their Webmaster Tools account and any contact email addresses we can find on the webpage. We hope webmasters will also appreciate these notices, because it will help you more quickly discover when someone may be abusing your site so you can correct the problem."
Written by: Andre Yoskowitz @ 20 Dec 2010 1:11
