Things like BetFair let you place bets both sides (unlike some shops like Ladbrokes where you are betting against them). This allows you to track the current be

Things like BetFair let you place bets both sides (unlike some shops like Ladbrokes where you are betting against them). This allows you to track the current betting prices and create situations where no matter the outcome you can make money. There are a few places on the net explaining this in more detail.