Some scholars believe the @ symbol dates back to the sixth century, when scribes simplified the Latin word ad (at) by exaggerating the upstroke of the letter d and curving it over the a. Others believe that the symbol had its genesis in sixteenth-century Venetian trade as an abbreviation for amphora, a standard-size terra-cotta vessel employed by merchants that became a unit of measure. The word à in Norman French might be another source for @, which was adopted in northern Europe to mean "each at," indicating price, its accent eventually becoming @'s curl. Since the nineteenth century, @ has appeared on standard typewriter and computer keyboards as the "commercial a," used, until fairly recently, almost exclusively by accountants to mean "at the rate of."
In 1967, Tomlinson joined the technology company Bolt Beranek and Newman, where in 1971 he created the world's first e-mail system for the United States government's Advanced Research Projects Agency Networks (ARPAnet). He adopted @ as a stand-in for the long and convoluted programming language indicating a message's destination. This was a design decision of extraordinary elegance and economy—repurposing an existing, available, and underutilized symbol to adapt the standard keyboard to a revolutionary new technology. The sign's new function is in keeping with its origins: in computer language, as in financial transactions, @ designates a relationship between two entities, establishing a link based on objective and measurable rules. The sign is now part of everyday life all over the world, demonstrated by the affectionate names it has in different cultures. Germans, Poles, and South Africans call @ "monkey's tail," Chinese see a little mouse, and Italians and French a snail. The Finnish know it as the miukumauku, the "sign of the meow," because it resembles a curled-up sleeping cat.
from Born out of Necessity, March 2, 2012–January 28, 2013