Voting, is not useless. The electoral college was implemented in order to represent the population of a given state back before people could travel to the election sites. Remember, it took days to travel any distance at all when this system was implemented. The electoral votes are winner take all, so in one stance the general election popular vote does not matter, think Al Gore in 2000. What does matter is the popular vote in each state. As a rule of thumb, the Electoral College will award the winner of your state's popular vote all of the states electoral votes. The winner of the most electoral votes wins the general election.
The use of the electoral college is a debatable issue. On one hand, it makes dissenting votes in a non-swing state meaningless. For instance, if your state is a heavily democratic state, your vote for a republican (while it counts) really has no impact on the election. On the other hand, it prevents grossly populated states from having total control of the election. Urban areas tend to vote democratic and the majority of people in the united states live in metropolitan areas. If the popular vote was all that counted, California, New York, Illinois and Georgia would have a huge influence on the election while entire states like Iowa or Alaska (which are lightly populated) would not have any significance at all. It gives with one hand and takes away with the other.
Ron Paul 2012.