Online poker is the game of poker played over the Internet. It has been partly responsible for a dramatic increase in the number of poker players worldwide. Christiansen Capital Advisors stated online poker revenues grew from $82.7 million in 2001 to $2.4 billion in 2005, while a survey carried out by DrKW and Global Betting and Gaming Consultants asserted online poker revenues in 2004 were at $1.4 billion.
Traditional (or "brick and mortar", B&M, live) venues for playing poker, such as casinos and poker rooms, may be intimidating for novice players and are often located in geographically disparate locations. Also, brick and mortar casinos are reluctant to promote poker because it is difficult for them to profit from it. Though the rake, or time charge, of traditional casinos is often high, the opportunity costs of running a poker room are even higher. Brick and mortar casinos often make much more money by removing poker rooms and adding more slot machines.
Online venues, by contrast, are dramatically cheaper because they have much smaller overhead costs. For example, adding another table does not take up valuable space like it would for a brick and mortar casino. Online poker rooms also allow the players to play for low stakes (as low as 1¢/2¢) and often offer poker freeroll tournaments (where there is no entry fee), attracting beginners and/or less wealthy clientele.
Online venues may be more vulnerable to certain types of fraud, especially collusion between players. However, they have collusion detection abilities that do not exist in brick and mortar casinos. For example, online poker room security employees can look at the hand history of the cards previously played by any player on the site, making patterns of behavior easier to detect than in a casino where colluding players can simply fold their hands without anyone ever knowing the strength of their holding. Online poker rooms also check players' IP addresses in order to prevent players at the same household or at known open proxy servers from playing on the same tables.
Free poker online was played as early as the late 1990s in the form of IRC poker. Planet Poker was the first online cardroom to offer real money games. The first real money poker game was dealt on January 1, 1998. Author Mike Caro became the "face" of Planet Poker in October 1999.
The major online poker sites offer varying features to entice new players. One common feature is to offer tournaments called satellites by which the winners gain entry to real-life poker tournaments. It was through one such tournament on PokerStars that Chris Moneymaker won his entry to the 2003 World Series of Poker. He went on to win the main event, causing shock in the poker world, and beginning the poker boom. The 2004 World Series featured three times as many players as in 2003. At least four players in the WSOP final table won their entry through an online cardroom. Like Moneymaker, 2004 winner Greg Raymer also won his entry at the PokerStars online cardroom.
In October 2004, Sportingbet, at the time the world's largest publicly traded online gaming company (SBT.L), announced the acquisition of ParadisePoker.com, one of the online poker industry's first and largest cardrooms. The $340 million dollar acquisition marked the first time an online cardroom was owned by a public company. Since then, several other cardroom parent companies have gone public.
In June 2005, PartyGaming, the parent company of the then largest online cardroom, PartyPoker, went public on the London Stock Exchange, achieving an initial public offering market value in excess of $8 billion dollars. At the time of the IPO, ninety-two percent of Party Gaming's income came from poker operations.
In early 2006, PartyGaming moved to acquire EmpirePoker.com from Empire Online. Later in the year, bwin, an Austrian based online gambling company, acquired PokerRoom.com. Other poker rooms such as PokerStars that were rumored to be exploring initial public offerings have postponed them.
As of March 2008, there are fewer than forty stand-alone cardrooms and poker networks with detectable levels of traffic. There are however more than 600 independent doorways or 'skins' into the group of network sites. As of January 2009, the majority of online poker traffic occurs on just a few major networks, among them PokerStars, Full Tilt Poker and the iPoker Network.
As of February 2010, there are approximately 545 online poker websites. Within the 545 active sites, about two dozen are stand-alone sites (down from 40 in March 2008), while the remaining sites are called “skins” and operate on 21 different shared networks, the largest network being iPoker which has dozens of skins operating on its network. Of all the online poker rooms PokerStars.com is deemed the world’s largest poker site by number of players on site at any one time.