Are you a real writer once you've written something? Does the mere act of writing make you a writer? Or are there metrics that you have to reach? Some obvious ones, in order of increasing difficulty/snobbery:
Shown it to someone else.
Revised it based on input.
Submitted something for publication.
Gotten something published.
Gotten paid for something you've written.
Made a profit on one single thing you've written, i.e. (what you were paid) > (time & materials invested).
Made a profit on at least 5 things.
Made a profit of one month's expenses.
Made a profit of one year's expenses.
Sold a short story.
Sold 5 short stories.
Sold a book.
Sold 3 books.
Gotten an advance on an unfinished book.
Gotten an advance on an unfinished book from a major house.
Had a substantially profitable book.
Had a best seller.
Had 3 best sellers (to prove the first one wasn't just a fluke).
Made enough to quit your day job.
Been optioned for some kind of spin-off from your book (calenders, wrist bands, inspirational coffee mugs, etc.)
Been optioned for new creative work based on your book (movies, TV shows, pulp fiction set 'in the universe of...', line of action figures, etc.)
Won an award.
Won a major genre award (Hugo, Edgar Allen Poe, Newberry).
Won a major literature award (Booker, Pulitzer, Nobel).
When does it count?
Update: this is a repost. I like the comments on this one, so I've carried it forward so the comments can be seen.