The document introduces several major social media sites and provides their founding dates and locations. Google was founded on September 4, 1998 in Menlo Park, California. YouTube was founded on February 14, 2005 in San Mateo, California and was later acquired by Google. Facebook was founded on February 4, 2004 in Cambridge, Massachusetts. Yahoo was founded on March 2, 1995 in Santa Clara, California. Twitter was founded on March 21, 2006 in San Francisco, California.