Straight from that article, I think this sums it up best:
Looking at that site thought, the video shows some references to Family Guy jokes mirroring the Simpsons. While there is some joke stealing going on, some of the examples are the same situations but they are either told differently or with different outcomes.To take a successful show and re-make it three different ways is either a reflection on the unoriginality of the creator, or the gullibility of the public - or both
The writing staff from The Simpsons aren't completely innocent either. Some of their older writing staff had publicly stated that they would often steal ideas from Disney.
Summary: Fox makes tens of billions of dollars on the simpsons franchise, but chokes when asked to pay the main voice actors a total sum of $30m per season.