This is a pretty interesting paper by Cisco that is part of their"ongoing initiative to track and forecast the impact of visual networking applications." If you are curious to see how video uploads and downloads will potentially affect the Internet through 2012, take a look at this paper.
By the way, a Zettabyte is 1,000 exabytes. An exabyte is 1,000,000,000,000,000,000 bytes or 1,000,000,000 gigabytes. Let's just say it's lots of data. Lots.