From what I gathered reading the 2009-2010 thread, deferred means they have looked over your application, and have not offered you an interview at this time, but they may look over your app later and change their mind (this happened to like 2 people in the thread last year). People that are complete, I'm guessing their apps aren't done the screening process yet. A lot of people that were still just left at "complete" last year at this time were ultimately offered interviews, but I kinda think they didn't update today. I'd be really surprised if no one on SDN was deferred, or maybe just no one decided to post about it.
Basically, it seems like the difference between "Uh, we still don't know," and "Probably not."