He is saying how throughout his life his being of "yellow" color has influenced the way he has been percieved as. He is not being noticed as a man or a woman, white or black, but as nothing or in his words vanishing. People, mainly whites, have seen him as transparent or as i would say don't even see him at all. There is no place in history for him to fit in. He give the example of the bus. consisting of whites in the front and blacks in the back. Where does yellow fit in? no where in he believes.

There are many cases that you could use this in. They don't all necessarily have to do with race, maybe they deal with popularity/social outlook. Maybe a kid in class gets made fun of or has no "group" to fit hisself into because he/she is out of the social norm. Kids can be discriminated against because of how they dress or what music they listen to. Discrimination doesn't always deal with race.