As someone whose email address is posted in thousands of forum posts, newsgroup discussions, and blogs, I get a lot of spam. Of the spam I receive, a significant number of messages represent phishing attacks. Most of these lures aren’t very clever or convincing, but phishing has become a simple numbers game—hosting phishing sites is cheap, and even if only a few users fall for any given phishing attack, attackers will profit by increasing the volume of phishing campaigns.

In Internet Explorer 7, we introduced the Phishing Filter, a dynamic security feature designed to warn users when they attempt to visit known-phishing sites, and worked with partners to introduce Extended Validation certificates that light up the address bar when users visit sites with verified identity information. Beyond the Phishing Filter, Microsoft has also published educational materials on identifying phishing scams, and developed a strategy to attack phishing at multiple levels.

For Internet Explorer 8, we’ve built upon the success of the Phishing Filter feature (which blocks over a million phishing attacks weekly) to develop the SmartScreen® Filter, a replacement that improves upon the Phishing Filter in a number of important ways:

• Improved user interface
• Faster performance
• New heuristics & enhanced telemetry
• Anti-Malware support
• Improved Group Policy support

Source- IE Blog