Translation for our North American friends:-

punter n. The nearest equivalent to an omnisex version of bloke. A punter is usually a customer of some sort, but this need not be the case. I believe that originally a punter was someone placing bets at a racecourse. However, as the language developed natural progression decreed that, as the greater proportion of the British public were susceptible to a flutter, it described almost all of us. However, because of the word's gambling roots, punters are regarded slightly warily and shouldn't be taken at face value. In the US, the punter is the member of an American Football team charged with punting the ball a decent distance.

courtesy of http://english2american.com/