Bobman is right on. Most building products contain chemicals that can be harmful in large doses over extended periods of time (ie: years, if not decades), and cellulose insulation is no different. Very safe, benign product in this application, and when applied correctly. It is possible that you would experience some irritation from breathing in a good chunk of the dust, but nothing more than that... There is probably more harm in the off-gassing from various items around your home, and certainly more in most of the delicious processed food that we eat.
... I also have to say that whether or not there is truth to the "stories" contained in that link, it is hardly a scientific study and should therefore not be given much credence. They are filled with incompetent workmanship, and a lack of common sense by multiple parties. Clearly, nobody should stay in their home for any amount of time if the have a 1/2" layer of loose insulation of any sort coating all of the surfaces.