Digital data is growing by a factor of 10 every five years. 1 bit = a single electronic "switch" in a computer. 1 byte = a sequence of 8 switches.   1 megabyte = a small book. (1,000,000 or 106)   1 gigabyte = 20 meters of shelved books. (1,000,000,000 or 109)   1 terabyte = an academic research library. (1,000,000,000,000 or 1012) In 2007, the amount of digital information created worldwide was 281 Exabytes (an Exabyte is a billion Gigabytes or 1018 bytes). A Zettabyte (1,000,000,000,000,000,000,000) is equal to 1,000 exabytes. A Zettabyte is about 0.0016 moles of bytes. "By 2011, there will be 1.8 Zettabytes of electronic data stored in 20 quadrillion (20 million billion) files, packets or other digital containers. Internet traffic worldwide will be ~1 Zettabyte per year. Most of that digital traffic will be video and other "rich" media. By 2023 the number of stored bytes will surpass Avogadro's number, 602,200,000,000,000,000,000,000 (6.022 x 1023) bytes. Then we can begin referring to Yottabytes (1024) of data.