By Verena Dobnik, Associated PressNEW YORK -- A co-founder of Reddit and activist who fought to make online content free to the public has been found dead, authorities confirmed Saturday, prompting an outpouring of grief from prominent voices on the intersection of free speech and the Web. Aaron Swartz, 26, hanged himself in his Brooklyn apartment weeks before he was to go on trial on accusations that he stole millions of journal articles from an electronic archive in an attempt to make them freely available. If convicted, he faced decades in prison and a fortune in fines. He was pronounced dead Friday evening at home in Brooklyn's Crown Heights neighborhood, said Ellen Borakove, spokeswoman for New York's chief medical examiner. Police went to the apartment after receiving a 911 call from Swartz's girlfriend, who found him. "Aaron's insatiable curiosity, creativity, and brilliance; his reflexive empathy and capacity for selfless, boundless love; his refusal to accept injustice as inevitable -- these gifts made the world, and our lives, far brighter," Swartz's family said in a statement Saturday. "We're grateful for our time with him, to those who loved him and stood with him, and to all of those who continue his work for a better world." Swartz was "an extraordinary hacker and activist," the Electronic Frontier Foundation, an international nonprofit digital rights group based in California wrote in a tribute on its home page. He "did more than almost anyone to make the Internet a thriving ecosystem for open knowledge, and to keep it that way," the tribute said. Swartz was a prodigy who as a young teenager helped create RSS, a family of Web feed formats used to gather updates from blogs, news headlines, audio and video for users. He co-founded the social news Web site Reddit, which was later sold to Conde Nast, as well as the political action group Demand Progress, which campaigns against Internet censorship. But Swartz struggled with depression. "Surely there have been times when you've been sad," he wrote in a 2007 blog post. "Perhaps a loved one has abandoned you or a plan has gone horribly awry. Your face falls. Perhaps you cry. You feel worthless."