Someone says that a sign up form with the label What is your email? is correct, and I'd argue that, since "email" is only a "method of exchanging messages", it makes that text incorrect, and that What is your email address? should be used instead.
Can the first text be considered a mistake, as I believe, or it's an accepted expression?
While "email address" is technically the correct term, it has become extremely common to use "email" as a shorthand for it. I can't find any online dictionaries that acknowledge this sense, but I see it used all the time, Especially in form prompts, which usually need to be terse.
There's little ambiguity, because in a phrase like "your email" it's not likely that they mean "system of exchanging messages" -- this is a concept that doesn't belong to any individual.
