Major email providers like Gmail, Hotmail, and AOL have dramatically improved their spam filters in recent years. However, if you're receiving a disruptive level of unwanted communications, effectively web-based anti-spam solutions are available. Google's postini is one of the best out there as anti-spam solution. You can easily integrate it with an existing email service. Postini is my favorite as a blogger in combating spam, viruses, phishing, denial of service and other attacks. One have to safeguard their resources from malicious or unwanted mails or applications. Postini will basically monitor your email through its gateway, preventing spam from ever reaching your inbox.