A federal appeals court, in the first decision of its kind, said Thursday that companies providing malware, spyware and adware blocking services are immunized by the Communications Decency Act of 1996. A three-judge panel of the 9th U.S. Circuit Court of Appeals found that the CDA treats security software makers the same as internet service providers when they block material they find objectionable. Like an ISP, such companies provide an interactive computer service because they pull updates from a central server.
Source: https://threatpost.com/court-rules-favor-kaspersky-filtering-case-063009/72826/