Google Safe Browsing is a service provided by Google that provides lists of URLs for web resources that contain malware or phishing content. The Google Chrome, Apple Safari and Mozilla Firefox web browsers use the lists from the Google Safe Browsing service for checking pages against potential threats. Google also provides a public API for the service.
Google also provide information to Internet Service Providers, by sending e-mail alerts to Autonomous System operators regarding threats hosted on their networks. According to Google, as of June 2012, some 600 million Internet users were using this service, either directly or indirectly.
To use this service put in or copy into your web browser address bar or just click on (and then change) http://www.google.com/safebrowsing/diagnostic?site=mysite.com, the last name needs to be the url of the webpage or site you wish to find out about.
Article Source - wikipedia