The Internet generates a lot of traffic. Cisco reports that this year global IP traffic on the Internet is expected to exceed 21,000 petabytes per month (a petabyte is about 1 million gigabytes) and the total volume is expected to increase by almost one-third every year. At the per-connection level, Cisco found that the average broadband connection generates almost 15 GB of Internet traffic per month. So what is all this traffic? And how much of this traffic is being used for legitimate content...