The game of poker, played over the Internet, is what online poker refers to. It has partial responsibility for the dramatic increase in the number of poker players worldwide. According to Christiansen Capital Advisors, online poker profits increased from $82.7 million in 2001 to $2.4 billion in 2005, while a questionnaire done by DrKW and Global Betting and Gaming Consultants said that online poker revenues in 2004 reached $1.4bn.

Traditional (or “brick and mortar”, B&M, live) venues to play poker, like casinos as well as poker rooms, can be intimidating for beginning players, plus they are often located in locations that can be difficult to get to. Also, it is difficult for brick and mortar casinos to profit from poker so most of them are reluctant to promote it. The costs of running a poker room are even higher, though, than the often already high rake, or time charge, of traditional casinos. By removing poker rooms and adding more slot machines, brick and mortar casinos are often able to make much more money.

Due to lower overhead expenses, online poker venues tend to have noticeably cheaper costs than traditional venues. Adding another table, for example, does not take up valuable space like it would for a brick and mortar casino. Online poker rooms often offer free roll tournaments in poker with no entry fee and, in addition, allow the players to play for stakes which are low, 2 or 3 cents, in order to attract beginners.

Certain types of fraud, especially collusion between players, is a weakness of online venues. They have collusion detection abilities, however, that do not exist in brick and mortar casinos. As an example, the hand history of the cards that have been previously played by any player that is on the site can be viewed by the security employees of an online poker room, making detection of patterns of behavior easier than in a casino where players in collusion can fold their hands without anybody detecting their holding’s strength. To prevent players at the same household or at known open proxy servers from playing on the same tables, Online poker rooms also check players’ IP addresses.

Online poker, under the name IRC poker, was free and began in the late 1990s. The first online card room to offer real money games was Planet Poker. On January 1, 1998, the first real money poker game was dealt. In October, 1999, author Mike Caro became the “face” of Planet Poker.

To entice new players, major online poker sites offer varying features. Tournaments called satellites, by which the winners gain entry to real-life poker tournaments, is one common feature offered. Chris Moneymaker won his entry to the 2003 World Series of Poker through one such tournament on PokerStars. His triumphant winning of the main event shocked the poker circuit. Three times as many players were featured in the 2004 World Series as were in 2003. Online card rooms were the method of gaining entries into the WSOP for at least four of the players that reached the final table at the tournament. 2004’s winner, Greg Raymer, won his entry the same way Moneymaker did — at PokerStars.

The acquisition of ParadisePoker, one of the first and biggest card rooms in the online poker industry, in October 2004, was announced by Sportingbet, the world’s largest publicly traded online gaming company (SBT.L), at the time. The first time a public company owned an online card room was marked by this $340 million acquisition. Many other card room parent companies have gone public since then.

PartyGaming, parent company of PartyPoker, the then biggest card room online, went public on the Stock Exchange of London, in June 2005, achieving a market value of larger than $8 billion initial public offering. When the IPO took place, poker operations were the source of 92% of the income of Party Gaming. To acquire EmpirePoker.com from Empire Online, PartyGaming moved in early 2006. Bwin, an Austrian based online gambling company, acquired PokerRoom.com later in the year. PokerStars and other online card rooms that were rumored to be looking into initial public offerings have postponed them for now.

There are less than forty stand-alone card rooms and poker networks with detectable levels of traffic, as of March 2008. However, there are more than 600 independent doorways or ’skin’s’ into the group of network sites. The majority of online poker traffic occurs on just a few major networks, as of January 2009. Among them are PokerStars, Full Tilt Poker, and the iPoker Network. Full Tilt Poker is where the vast majority of high stakes action takes place, with the 2008 top ten winning players all coming from this site.