New York -- New York City drugstore operator Duane Reade, a division of Walgreens, on Tuesday celebrated an important social milestone — surpassing one million followers on Twitter — with a gala event at the chain’s flagship on Wall Street. From September 2012 to date, the regional retailer has organically grown its Twitter following by 6,709%, making it one of the fastest-growing accounts on Twitter year over year. With 1.1 million followers at latest count, the chain is believed to be the most followed retailer in the drug, food and mass arena.