Poker's popularity experienced an unprecedented spike at the beginning of the 21st century, largely because of the introduction of online poker and hole-card cameras, which turned the game into a spectator sport. Not only could viewers now follow the action and drama of the game on television, they could also play the game in the comfort of their own home. Broadcasts of poker tournaments such as the World Series of Poker and World Poker Tour brought in huge audiences for cable and satellite TV distributors.

Because of the increased coverage of poker events, poker pros became celebrities, with poker fans all over the world entering into expensive tournaments for the chance to compete with them. Television coverage also added an important new dimension to the poker professional's game, as any given hand could now be aired later, revealing information not only to the other players at the table, but to anyone who cared to view the broadcast.

Since 2003, major poker tournament fields have grown dramatically, in part because of the growing popularity of online satellite-qualifier tournaments where the prize is an entry into a major tournament. The 2003 and 2004 World Series of Poker champions, Chris Moneymaker and Greg Raymer, respectively, won their seats to the main event by winning online satellites.

 After the passage of the UIGEA in October 2006, attendance at live tournaments as well as participation in live and online cash games initially slowed, however they are still growing and far more popular today than they were prior to 2003. The growth and popularity of poker can be seen in the WSOP which had a record 6,844 entrants to the main event.

Poker is a family of card games that share betting rules and usually (but not always) hand rankings. Poker games differ in how the cards are dealt, how hands may be formed, whether the high or low hand wins the pot in a showdown (in some games, the pot is split between the high and low hands), limits on bets and how many rounds of betting are allowed. In most modern poker games, the first round of betting begins with some form of forced bet.

The action then proceeds to the left. Each player in turn must either match the maximum previous bet or fold, losing the amount bet so far and all further interest in the hand. A player who matches a bet may also raise, increasing the bet. The betting round ends when all players have either matched the last bet or folded.