300 billion -- That's how many 0's and 1's were sent per second as part of the largest-ever cyberattack, according to Internet secruity firm CloudFlare. That rate is nearly 50,000 times greater than the average U.S. Internet connection. The attack last week from unknown sources reportedly slowed Web traffic across Europe. This strike stands out because it targeted the servers that allow the Internet to function, not disrupting only a single website. The attack is a fresh reminder of major threats we face in an increasingly digital world -- and the need to guard against them.