Betting sites are now legal in a handful of states. This follows the removal of the ban that had prevented most of America of from offering sports betting.
Each state is different in: a) rules and regulations around tax rate and license fee, b) how open the market is and c) how many operators are permitted. In other words, the number of betting sites and the operators authorized varies from state-to-state.
In New Jersey, for instance, a friendly market awaits operators in terms of tax rate and license fee. There's also no limit on the number of sites which creates a competitive market for bettors, who, in turn, can enjoy the freedom of remote registration and online wagering. The result of all this is the best performing online betting market in the country.
Pennsylvania, West Virginia, Indiana and Colorado all follow similar 'open' models, hence why you'll find FanDuel and DraftKings and other popular betting sites in these states.
Oregon, on the other hand, has just one online wagering option: The Scoreboard. The market in the Beaver State is controlled by the state lottery who has given one operator a monopoly of the market. New Hampshire and Rhode Island are also examples of states that have decided to go with a sole operator.