"What is your definition of deep and shallow?" - I think about this from a more functional perspective. Generalist vs. specialist. There are people who cultivate multiple friendships and many interests, more broadly, and people who cultivate few friendships and fewer interests, more deeply. I think everyone has the capacity to be deep or broad, but they also have a natural tendency.
"Which one do you consider yourself and why?" - I wouldn't say shallow, but I would just say I am naturally more general or broad-minded... global.
"Which one do you consider most people you know or "at large" (and why)?" - No clue. I think extraversion might be the link so I would guess shallow.