In 2006, the Federal Bureau of Investigation (FBI) processed more than two petabytes of digital evidence; in 2007, the volume of digital evidence processed will exceed four petabytes. Electronic devices are becoming smaller and more diverse; memory capacities are increasing according to Moore's Law; distributed networks are growing massively in size and scale. As society embraces new technologies and applications with gusto, digital information will become even more pervasive. Digital investigations already involve searching for the proverbial nee- dle in the haystack. In five years, possibly...