Internet-based business disruptions triggered by worms and viruses are costing companies an average of <A HREF="http://zdnet.com.com/2100-1105_2-5258769.html?tag=zdnn.alert">nearly $2 million in lost revenue</A> per incident, market researcher Aberdeen said. Out of 162 companies contacted, 84 percent said their business operations have been disrupted and disabled by Internet security events during the last three years.