Swartz, Huffman, and Ohanian are the only YC participants they interview, and they show them all working side-by-side, so I assumed they were all working on Reddit, but I just checked how they introduce Swartz and his title card doesn't say Reddit whereas Huffman and Ohanian's do.
I've corrected the post.
Wasn't he involved sooner than a year after? I thought it launched in Summer 2005, and then Swartz joined the same year.
>Over at reddit.com, we rewrote the site from Lisp to Python in the past week.
Aaron Swartz's blog post, "Rewriting Reddit," published 2005-12-06
Aaron didn't launch reddit. He wasn't even involved until six months in.