Online betting exchange has become very popular in the past five years.  For those who do not know what a betting exchange is, it is a form of gambling that let's players post odds on a variety of events (mostly sports events), which other players may then challenge or bet with.  Bettors can make a large variety of picks, including which horses they believe will lose a race, or, placing winning odds on one team in a football match.  In many ways, the service resembles an online poker room, in that no money is lost to the betting exchange service.  Rather, it is transferred from bettor to bettor, while the exchange service takes a fee for using it as a mediator.

The largest and most popular online betting exchange service by far is BetFair.  Based in the UK, BetFair brings in approximately $250 million in revenue per year, and now has over 500,000 members using the service to make bets online.  Much of the action that goes on at BetFair is over the racing industries (horse and greyhound) as well as international soccer, although coverage is offered on a large variety of major and minor sports and various leagues.

According to BetFair, U.S. residents are not permitted to open accounts and make transactions with US debit/credit cards - not that BetFair is opposed to doing so by no means.  However, U.S. racing officials (who are themselves opposed to betting exchanges in the U.S.) believe that BetFair does indeed accept wagers from U.S. players over the internet. 

In response to this sentiment, BetFair U.S. Business Development Director, Christian Hellmers was on record in the UK Bloodhorse saying that the BetFair betting exchange service could generate $50 million per year for itself, racetracks and horsemen, if the company was permitted to tap into the U.S. market.  BetFair strongly believes that online betting exchange in the U.S. would increase the betting market by 59% and generate substantial revenue in tax dollars and for the U.S. horse racing industry.