The attribute email is used to describe that some string is an email address.
If you want to state an (annotated) email address in some article, the easiest way is to use the semantic templates Template:Mailbox (for emails of persons and organisations) or Template:Email (for emails of things that are not "agents" in the sense of FOAF). The usage of both templates is simple, and documented on their respective pages.
Note: "Electronic mail" is commonly abbreviated both as "e-mail" and as "email". Using "email" we rank common usage above linguistic reason – a choice that seems to have a good tradition in English language ;-) See The Internet for extensive discussion of the subject.