Quoting from The Elements of Typographic Style, a good use of em dashes is to introduce speakers in a narrative dialogue. This is inspired by the European style, and is less fussy than quotation marks:
Taking a slightly different approach,
Instead of
Q: How are you
A: I am fine.
I've used
— How are you
— I am fine
for an interview spread which I am designing.
I've seeking for feedback whether would this way of marking interview dialogues be a feasible one. Suggestions are much appreciated.

