A free browser extension from anti-virus manufacturer Finjan for Internet Explorer and Firefox, called SecureBrowsing http://securebrowsing.finjan.com/, alerts users of potentially dangerous links in Google Search and other popular sites and online portals. The add-on marks links using three different colour icons. Green lets users know that the page should be safe for browsing, yellow indicates that the page is not available for scanning and red advises users that the page contains “potential spyware behavior”. Links to popular services including Twitter, MySpace, Digg and Slashdot, as well as online mail services such as GMail, Yahoo and Hotmail are also verified. Shortened URLs, like those found on the popular Twitter microblogging service, from sites like TinyURL and Cligs, are checked and labeled with the applicable icon.