Well, not quite different enough to suit some folks. The thumbnail picture being the same, the title being almost the same... and not really significant differences in the text. Here comes the part where you get sorry you asked... lol!
Upvotes are paid out of the reward pool, there is only so much money generated per day that goes into the reward pool. People get twitchy if they think you are trying to double dip it on one post. They like to see original material. Now, you are going to see people putting up crap, just crap, and getting crazy payouts that will make you think "Why isn't fishy bitching at them?" and the answer is sad and simple: I cannot do anything about abusive whales. They exist, and if you piss them off they will destroy smaller accounts... but MOST of us are trying to create good content and play fair.
Peace!