Yes, Aaron was the co-founder of Reddit and Avaaz. Aaron edited and contributed to the RSS specifications when he was 14. But that isn't the best part. Even for people like me, who only met Aaron on the internet, he was a lot more. From Remember Aaron:
Aaron's commitment to social justice was profound, and defined his life. He was instrumental to the defeat of an Internet censorship bill; he fought for a more democratic, open, and accountable political system; and he helped to create, build, and preserve a dizzying range of scholarly projects that extended the scope and accessibility of human knowledge. He used his prodigious skills as a programmer and technologist not to enrich himself but to make the Internet and the world a fairer, better place. His deeply humane writing touched minds and hearts across generations and continents. He earned the friendship of thousands and the respect and support of millions more. Aaron's death is not simply a personal tragedy. It is the product of a criminal justice system rife with intimidation and prosecutorial overreach.
I think it's worth repeat those words again: used his prodigious skills as a programmer and technologist not to enrich himself but to make the Internet and the world a fairer, better place.
Lawrence Lessig has called for this tragedy to be a basis for reform of computer crime laws, and the overzealous prosecutors who use them. You can read more about Aaron and the case also in the EFF's farewell.