Hi CodeForces!

Recently, I've started doing contests on CodeForces and when my rating jumped I was obsessed with contests, ratings,.... I was wondering how do rating changes, is there any rule, or is there any formula... And after some research, I found this site:http://codeforces.net/blog/entry/102.

I was discussing with my pals about one interesting thing, you can not(obviously it is possible) get rating change 0. I mean, there is a very little chance for you to break the formula and get infinity(and beyond!).

I thought that if someone succeed in breaking the formula, CodeForces would give him +1 or -1 or some similar value, oh boy was I wrong! When I finished my last contest (Div 2. #442), which I did terribly (solved only problem A, (average for me is B and sometime C) and one hack), I was waiting for results. The NoButtHurt extension didn't work on me, I thought okay bug, it happens... My friends got their results (and rating change) and I didn't. I was waiting and waiting and waiting...I mean there was a 0 but I thought that I am still in queue for calculating. Next morning my rating didn't changed, wow! I was shocked(so was my friends). Still trying to figure it out, did I "broke: the formula and got 1/0 rating change or idk.... Does anyone have any clue what happened? Maybe it's usual thing, did you ever got rating changed by 0?