[tkluck]

> some of the filings will fly up against gravity to the bar, against the force of gravity. It takes energy to lift these filings. Where does that energy come from?

In this example the energy comes from whatever is holding the bar magnet itself up against gravity. If it's not doing any work (ie. it's not adding energy; say it's a rope or a spring) then it's not just the filings that move: the bar magnet and the filings move towards each other (with the filings moving the bulk of the distance) and the end result is that some of the gravitational energy in the bar magnet is transferred to the filings.

I think this only seems like a tricky question with an informal idea of what "energy" is. It doesn't have the same interpretation problem as what the linked article is about.