Goths tend to have a dark and perverse sense of humor, a love of history, literature, and music, and far too many bottles of black nail polish. But trying to slot goths into orderly little sections is pretty much impossible. The spectrum of interests, styles, and activities is far too broad. Sometimes the clothes can be a clue, but not always. Just look for that appreciation of darkness--that's the most reliable indicator.
The "classic" goth music scene and the industrial music scene, there are people on both sides who shun the other. Some goths who like the "classic" look of velvet and lace look down upon goths who prefer fishnet and leather. Some goths who like pop-culture entertainments and things that are lighthearted are ostracized by others who believe that nothing is worthwhile unless it is obscure and dark. Like any culture, it has divisions and cliques.
Being goth is, in the end, a form of tribalism, a way for people of like interests and mindset to find each other and have a place to belong. Like most tribes, goths will often try to keep out those who are not "of" the tribe (hence the pretentiousness and disdain for "poseurs"). But it can also be a wonderfully welcoming and comfortable place for those who do fit in, and full of patience and enthusiasm for people who are genuinely interested in finding out what we're about. Goths will try to keep out those who don't belong and those who are interested in exploiting us because we look different and have interests outside the mainstream; but we will also try to protect our own. For someone who doesn't feel that they really "fit in" with mainstream culture, discovering gothdom can be a wonderful feeling.
Of course, this is just the URBAN definition - we needn't forget the extinct Germanic tribe.
However, another note, there is no such thing as "goth" literature, or "goth" architecture, despite what many would lead you to believe. Please refer to gothic
"Goths are not really that terribly different from any other subculture. They just dress more imaginatively"