It's called WoT (Web of Trust), and it's an add-on compatible with Chrome, Firefox, IE, Safari, and Opera browsers, so it is very universal.
Description wrote:Web of Trust is the leading website reputation rating tool and one of Mozilla’s most popular add-ons. Our safe surfing tool uses an intuitive traffic-light style rating system to help you see which websites are trusted when you search, surf and shop online.
WOT ratings are powered by a global community of millions of trustworthy users who have rated millions of websites based on their experiences. The WOT add-on provides reputation ratings to search results when you use Google, Yahoo!, Bing, Wikipedia and other popular sites, helping you protect your computer and personal information. Your online email account – Google Mail, Yahoo! Mail and Hotmail is also protected.