Deaf Culture - What is It?

Deaf Culture what is it? is the biggest question in my mind lately. I am a student of sign language finely, something i have wanted to study for years, finely getting the chance to do so. I have always wondered what Deaf Culture is. Is it just the fact that Deaf communicate with sign, or is there more to it. So far from what i have read it's a sorta sub culture of the american culture. What is it that makes it unique? Is it as simple as the language or is there more to it.
—sybersis