Anne Cai, writing for The Tech:
The accomplished Swartz co-authored the now widely-used RSS 1.0 specification at age 14, was one of the three co-owners of the popular social news site Reddit, and completed a fellowship at Harvard's Ethics Center Lab on Institutional Corruption. In 2010, he founded DemandProgress.org, a "campaign against the Internet censorship bills SOPA/PIPA."
Accomplished is right. Sounds like a cool guy.
See also: John Gruber’s thoughts on the sad news.