Diff 2/2: The second number is the difficulty you're shooting for and the first is the difficulty you hit. Even though difficulty 2 is no where close what's needed to solve a block, you submit it to the pool to show them that you're doing work. They pay you based on how many of these shares you submit.
AMU 0: If you have more than one miner these will show up as different numbers to let you know which miner submitted the share.
So now I have a question. Using that example, if difficulty 2 is nowhere close to what's needed to solve a block, that means that all work submitted while on a low difficulty is just worthless? This is something that I've been trying to understand for a while but haven't really found much concrete info about.