Helping to do something for the sake of you and your community should be the common good seeing that the other answers don't really make sense for an answer to this question.
In 1901, banker John Pierpont Morgan (1837-1913) purchased Carnegie Steel for some $480 million, making Andrew Carnegie one of the world's richest men. That same year, Morgan merged Carnegie Steel with a group of other steel businesses to form U.S. Steel, the world's first billion-dollar corporation.
In his final years, Carnegie's net worth was US$475 million, but by the time of his death in 1919 he had donated most of his wealth to charities and other philanthropic endeavors and had only US$30 million left to his personal fortune.