Founder: Reid Hoffman
Place started the business: In the living room

LinkedIn was officially founded in 2003. The site was launched on May 5th (affectionately referred to by employees as “Cinco de LinkedIn”) when the five founders invited about 350 of their most important contacts to join. At the end of the first month in operation, LinkedIn had a total of 4,500 members in the network. LinkedIn’s first “real” office was on Shoreline Road in Mountain View.