As computers become faster, smaller, ubiquitous, and interconnected, the rate at which we generate new data is growing exponentially. Sophisticated computational simulation techniques have made it fast and easy to create large volumes of data by modeling all kinds of physical phenomena. Meanwhile, digital sensors and sensor networks have simplified the process of collecting data from the real world. Moreover, the Internet has connected us to one another in a way that further facilitates creation and dissemination of information. In fact, Lyman and Varian estimate that new stored information grew at a rate of 30 percent a year from 1999 to 2002 and that we produced 5 exabytes (equivalent to about 37,000 new libraries the size of the Library of Congress) of completely new information in the year 2002 alone.