WASHINGTON, DC -- The consumer orgies of Black Friday, Small Business Saturday, and Cyber Monday have a rapidly growing nonprofit rival: Giving Tuesday, which celebrates its seventh year today. Begun by a coalition hoping to reinvigorate giving in the United States during the holiday season, Giving Tuesday has turned into a philanthropic juggernaut: Last year, the day moved at least $300 million to nonprofits by mobilizing hundreds of thousands of people, many of them infrequent donors, to give to charities of their choosing. Giving Tuesday champions the welcome spirit of ordinary donors and the amazing diversity of American charity. But when it comes to philanthropic giving in the United States, it proves the exception to a stubborn rule. -- Opinion piece by Rob Reich, author of "Just Giving: Why Philanthropy Is Failing Democracy and How It Can Do Better." He is professor of political science and faculty co-director of Stanford University’s Center on Philanthropy and Civil Society.