[Haskell-beginners] unchecked exceptions as side effects

In this video Erik Meijer talks about side effects: https://www.youtube.com/watch?v=UuamC0T3hv8&t=6m and unchecked exceptions as side effects. I tried to read the paper "Unchecked Exceptions can be Strictly More Powerful than Call/CC" but I got lost pretty quick. Can somebody explain the matter nicely? Thanks, ovidiu