@cool_guy:
There is no doubt bai that hydrogen be used as a fuel either by combustion or used in a fuel cell. The article even sites that the electrolysis is one of the least efficient way of producing hydrogen. There is no mention of a car in that article that is run by water, it is run by hydrogen produced from an external source i.e fossil fuels or green energy like wind mills and etc.
Try and research about the entropy and the laws of thermodynamics and you will understand why electrolysis and combustion of hydrogen in a system to generate power is just not possible. It maybe hard to understand what entropy or thermodynamics at the beginning, i had a bit of a hard time on that Chemical Engineering days, but it will light the way for you.