Cloudmark
Cloudmark, Inc is a privately held company, San Francisco-based, providing protection against spam, viruses, phishing, and similar threats that affect email.
Cloudmark claims to protect about one billion subscribers for the world's largest carrier networks, including over 75 percent of all major service providers in the United States and Japan. Its client reference list includes: Cablevision, Comcast, Cox Communications, EarthLink, Rackspace, Reliance Connects, Swisscom, TDC, Orange, XS4ALL (KPN), as well as social networkings companies MySpace and probably Facebook.