Picture 12Reddit co-founders Steve Huffman and Alexis Ohanian are leaving the crowd-sourced news service when their contracts end on Oct. 31.

The pair helped found the social news site four years ago, and it was a promising competitor to Digg but never got quite the same traction. So it went open-source last year, after being acquired by Conde Nast (the parent company to Wired) in 2006. Based in Boston and backed by YCombinator, the group moved west after the sale.

Ohanian wrote in a goodbye post:

“After more than four years of thinking about reddit every day — it’s been more therapeutic than you know, actually — there’s bound to be some postpartum depression (and the only prescription, is more reddit). This is a special community that’s become a bigger part of my life than I ever could have imagined; I’m grateful for the opportunity to have worked with you all (except for the spammers).”

Ohanian’s going off to Armenia to serve as a Kiva fellow while Huffman says he’ll go to Virginia to spend time with his wife. A third Reddit programmer, Chris Slowe, is staying on even though his contract will also end. Huffman and Ohanian said the site will continue to operate as usual after they leave.