A difference is that Digg didn't keep the old design around. With Reddit you can simply use old.reddit and forget about the redesign while being in the same com

A difference is that Digg didn't keep the old design around. With Reddit you can simply use old.reddit and forget about the redesign while being in the same communities you were already (no need to wait for the entire community to move). Considering that Reddit already has two mobile interfaces (i.reddit.com - which i personally prefer due to it being very fast - and m.reddit.com) and two desktop interfaces, i doubt they'll drop old.reddit at any point. It is a form of backwards compatibility on a UX level.