Adele's nominated in Rock Song twice because she had huge success on Triple A and some moderate success on Alternative radio. Triple A and Alternative are Rock formats.
I really think Adele is a great artist , one of the best of this generation , but seriously it's enough . How can songs get nominated for Best Rock and Best Alternative and then the album from which they were spawned get nominated for Best Pop . It seems as if they just wanted to give her EVERY nomination . And what the hell is wrong with the Best Pop album finalists ? Bieber and Micheal and 19 being nominated over other pop artists... No shade