It is ironic that @ has become a trendy mark of Internet
awareness since it is a very old symbol, derived from the
latin preposition "ad" (at).

Giorgio Stabile, a professor of history in Rome, has traced
the symbol back to the Italian Renaissance in a Roman
mercantile document signed by Francesco Lapi on 1536-05-04.

In Dutch it is called "apestaartje" (little ape-tail), in
German "affenschwanz" (ape tail). The French name is
"arobase". In Spain and Portugal it denotes a weight of about
25 pounds, the weight and the symbol are called "arroba".
Italians call it "chiocciola" (snail).

# - number sign; pound; pound sign; sharp;crunch; hex
The pronunciation of "#" as "pound" is common in the US but a
bad idea; Commonwealth Hackish has its own, rather more
apposite use of "pound sign" (confusingly, on British
keyboards the pound graphic happens to replace "#"; thus
Britishers sometimes call "#" on a US-ASCII keyboard "pound",
compounding the American error). The US usage derives from an
old-fashioned commercial practice of using a "#" suffix to tag
pound weights on bills of lading. The character is usually
pronounced "hash" outside the US.
http://dictionary.reference.com/search?q=hash character