What is @ ?

[Tamdang]

We usually see the sign @ in email addresses .For example, dangttam@yahoo.com.What is the sign @ ? And How do we read it ? Thanks
http://vihocsinh.ucoz.com/

[nevertheless]

its called "at", you read it just like the preposition. Furthermore, people sometimes use it as a word, for instance: i'm @ home now. But you see it's just like an internet slang