I don't know which admin read mine, or what they thought of it. It was however accepted, my only bit of advice is to try something that isn't the norm.
When i wrote my back story i wrote it as a letter to my characters father, even though he knew the letters weren't going anywhere it was a way for him to vent his frustrations.
It also served as a handy way of explaining my back story without breaking character; as an example you could write - "Michael is a tough guy, he has killed loads of people!" Compared to - "2 tours in Iraq will take a lot out of a man, and i am no exception. It's a kill or be killed world out there and I'm not one to shy away from action"
Same basic explanation but one is more interesting to read (Also takes up more space)