...Although the bill does not include a cap or any other direct limitation on charitable deductions, it does reinstate a limitation on itemized deductions for individuals with incomes over $250,000 and married couples filing joint returns with incomes over $300,000. Most itemized deductions, including the charitable deduction, are reduced by the lesser of 3 percent of adjusted gross income over the threshold or 80 percent of itemized deductions. This limitation had expired in December 2010. The bill also phases out personal exemptions for taxpayers with incomes over the same thresholds.

www.guidestar.org/rxa/news/articles/2013/exempt-organizations-and-fiscal-cliff-legislation.aspx