Il charattere @ era usato 500 anni fa a Firenze indicava una misura di capacita: l'Anfora , il Museo di Arte Moderna di New York ha dichiarato la sua proprieta sul carattere in questione definendolo "opera d'arte"

Il carattere @ non è ricercabile su Google, viene ignorato.
Seguono i link a siti interessanti che ne parlano.

The at sign (@), also called the atmark, at symbol, or commercial at,
The Museum of Modern Art (MOMA) recently declared "ownership" of the @ character, elevating it to the status of  "work of art"... But you couldn't find this out by searching Google with the term "@"
Thai does not have an official name for @, but some people call it " 'ai tua yiukyiu" [the wiggling worm-like character]
Amara Prasithrathsint

** What an interesting topic to pursue. Thai does not have an official
coinage for the sign yet. But there is a nickname, which "?ai tua
yUkyU:" literally meaning "the wiggling worm-like character". The
"?ai" is an equivalent of ?a in Chinese, which is prefixed to a
person's name. "Tua" is character, body, shape. YUkyU: (unrounded
back vowel) is a sound symbol for the crooked way a worm moves.
Occasionally people will borrow the English name of the
sign. In textbooks, the problem is eliminated with the use of the
symbol itself.
Its use in business actually goes back to late medieval times. An Italian academic, Giorgio Stabile, a professor of the history of science at La Sapienza University, claimed recently to have found evidence of its use in the records of Florentine merchants nearly 500 years ago. At that time, it was either a unit of weight or of volume, representing one amphora, a measure that was based on the capacity of the standard terracotta jars that were then employed to transport grain and liquid about the Mediterranean (the capacity of an amphora was one thirtieth of a barrel). The sign was a handwritten letter A (for amphora), embellished in the typical Florentine script.