There's a documentary on YouTube called "The internet's own boy", if you want to learn more. Basically, he was offered a 6 month plea, but he would be a convicted felon, and basic logic/morality tells you that you shouldn't plead guilty to a crime that you didn't commit. However, the justice system is very imperfect, and often people plead guilty for reduced sentencing even if they're not guilty. He stood on principle until his legs gave out. they were already in millions spent in attorney fees. Not a shred of justice can be found in how Aaron's story ended.

https://web.archive.org/web/20140721052709/http://www.boston.com/metrodesk/2013/01/14/mit-hacking-case-lawyer-says-aaron-swartz-was-offered-plea-deal-six-months-behind-bars/hQt8sQI64tnV6FAd7CLcTJ/story.html

Robert Evan's did a Behind the Bastards episode on this back in December I believe.