The document discusses the concept of gentrification and how it has evolved over time. Gentrification originally referred to revitalizing deteriorating urban neighborhoods, but it often displaces the poor residents with wealthier ones. Researchers have studied the causes and impacts of gentrification, including how it reflects the tastes of new residents moving in. Cities like Toronto have experienced significant gentrification through private development and an emphasis on improving downtown areas, which has contributed to a lack of affordable housing.