The term "Porfiriato" is used to designate the period in Mexican history where the nation was dominated by Porfirio Diaz. Diaz controlled the Mexican government, with a few brief interludes, between the 1870s and the first decade of the twentieth century.
Whether one sees this period as a positive or a negative for Mexico overall is really a matter of perspective. What is certain is that Mexico experienced unprecedented economic and technological development during this time. Railroads and mines in particular flourished, as Diaz sought and received international investment for industrial projects. Under Diaz, traditional forms of farming started to give way to large-scale market-based agriculture, and millions of Mexican people moved to the cities. Mexico City in particular became one of the world's biggest metropolitan centers during Diaz's tenure, as many sought to improve their economic situation by moving to the cities. All of this growth might be characterized as a positive for the Mexican economy.
Yet, to an even greater extent than the United States, where the same period is known as the "Gilded Age," the period witnessed rampant inequalities, as wealthy industrialists, most with close ties to foreign firms, became wealthy, and the masses of Mexican people remained in poverty. Urbanization caused particularly shocking conditions in Mexican cities, and the economy, focused on capital goods, failed to produce consumer goods to improve the lives of most Mexican people.
Apart from the costs of modernization in Mexico, Diaz was also an authoritarian, essentially a dictator who silenced dissent by imprisoning and sometimes even executing his critics. Native peoples in particular suffered brutal persecution from the national government. In short, the Porfiriato witnessed extraordinary economic development, but at a tremendous cost.