Do black people in the USA differentiate between lighter and darker skinned blacks?

I wouldn't say all Black Americans differentiate between skin complexion differences, but there are many out there that do differentiate. You'll occasionally see this "differentiation" manifest itself into problems, you can probably find what I'm talking about in the internet. Also, I mean in general one can tell the physical difference between the darker skinned Black Americans and the lighter ones, so Black Americans can tell the difference like the rest of us non-Black Americans.