I looked her up on Wikipedia, I didn't know she's a bit of a hit in the States, something to do with being very poor, discovering she had an amazing voice and getting on Oprah and now her life is way awesome which I guess means she was only supposed to be a cameo on Glee but I thought she was great!
I was of the understanding that she was actually supposed to be part of the show this season. I don't know if something about that fell through, but I liked her too. She was cute!