During the dot-com boom of the late 1990s, large numbers of entrepreneurs and computer software professionals moved into the city, followed by marketing and sales professionals, and changed the social landscape as once poorer neighborhoods became gentrified. The rising rents forced many people, families, and businesses to leave. San Francisco has the smallest share of children of any major U.S. city, with city's 18 and under population at just 14.5 percent.
By 2001, the boom was over, and many people left San Francisco. South of Market, where many dot-com companies were located, had been bustling and crowded with few vacancies, but by 2002 was a virtual wasteland of empty offices and for-rent signs. Much of the boom was blamed for the city's "fastest shrinking population", reducing the city's population by 30,000 in just a few years. While the bust has helped put an ease on the city's apartment rents, the city remains expensive.
By 2003, the city's economy had recovered from the dot-com crash thanks to a resurgent international tourist industry. Residential demand as well as rents are on the rise again and as a result of such demand, city officials have relaxed building height restrictions and zoning codes to allow another wave of Manhattanization in the city in the form of very tall residential condominiums in SOMA such as One Rincon Hill, 300 Spear Street, and Millennium Tower. In addition to this, a major transformation of the neighborhood is planned with the Transbay Terminal Replacement Project, which if funded, is planned to be open by 2013 along with what will be the tallest skyscraper on the West Coast with a cluster of other supertall skyscrapers next to it.