Billionaire Philip Anschutz is quietly building a small empire of social sites

Worth an estimated $5 billion, Anschutz founded Qwest Communications and owns or controls stakes in some 100 businesses. Among them: railroads; oil companies; cattle ranching; wind farms; national park concessions; professional hockey, basketball and soccer teams; Regal Entertainment Group, the largest movie operator in the U.S.; the Staples Center and Kodak Theater in Los Angeles; the 02 Dome in London, where the late Michael Jackson planned 50 concerts; and movie production house Walden Media.

Read More Billionaire Philip Anschutz is quietly building a small empire of social sites