Sports gambling is not legal throughout the entire country (Nevada is the only state where it is legal). Illegal sports gambling is a $390 industry and has been able to thrive thanks to technology and the Internet. Many illegal bets are made online on multiple websites. Much of the technology can help monitor the gambling and could help keep tabs on gambling trends, see who and what people are betting, etc. So in the case that gambling is legalized (and taxed), the technology is already set up to assist.
Overseas, in Europe, sports gambling is legal and a thriving industry. Soccer is the main sport where sports fans gamble. There are many statistics for people to place bets: who will score first, score, type of goal. If sports gambling was legal in the United States, there are many sports for people to gamble on. People would be able to gamble on not just soccer, but basketball, baseball, hockey, and football. As a matter of fact, NBA Commissioner, Adam Silver, has mentioned the idea of legalizing sports gambling on professional basketball.