In 2002, digital storage surpassed non-digital storage for the first time, according to Martin Hilbert and Priscila Lopez.

FORBES: What Has Steve Jobs Wrought?

In a 2011 article for the scholarly journal Science, researchers Martin Hilbert and Priscila Lopez estimated that the entire processing power of the world's stock of general-purpose computers in 2007 more or less equaled that of one human brain (about 6.4 quintillion instructions per second -- the standard measure of computer speed).

CNN: Roboticist sees improvisation through machine's eyes