You can read more here:http://en.wikipedia.org/wiki/Binary_optionThe big difference is binary options have a fixed payout. Traditional options don't. The payout goes up the more you are 'right', i.e. if you buy a call because you think a stock will go up, the more it goes up (and the faster) the bigger your profits. However, it would follow that binary options are probably cheaper to offset the open-ended possibilities.