A Natural History of the @ Sign Part One: The many names of @ The "@" symbol. . . used by grocers and accountants throughout the English-speaking world to indicate a rate, or cost per unit, as in "10 gal @ $3.95/gal" [ten gallons at three dollars and ninety-five cents per gallon] has become the de facto delimiter in e-mail addresses, separating the user's name from the domain name. Although the ch