What was the importance of plessy v. ferguson?

The supreme court ruled that seperate facilities for blacks and whites were legal, as long as they were of equal quality.  This "seperate but equal" standard, however, was not upheld, and black facilities were frequently much shabier.  Also, although some found it fair, the decision to seperate any group of people based on their race contributed greatly to the growing mentality of segregation and racism in the country.