Free poker online was played as early as the late 1990s in the form of IRC poker. PartyPoker, with both real-money games and free-play games, has been a trusted leader in gaming online since 1997.

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.

In June 2005, PartyGaming, the parent company of 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.

One obvious difference is that players do not sit right across from each other, removing any ability to observe others' reactions and body language. Instead, online poker players learn to focus more keenly on betting patterns, reaction time, speed of play, use of check boxes/auto plays, opponents' fold/flop percentages, chat box, waiting for the big blind, beginners' tells, and other behavior tells that are not physical in nature. Since poker is a game that requires adaptability, successful online players learn to master the new frontiers of their surroundings.

Another less obvious difference is the rate of play. In brick and mortar casinos the dealer has to collect the cards, shuffle, and deal them after every hand. Due to this and other delays common in offline casinos, the average rate of play is around thirty hands per hour. However, online casinos do not have these delays. The dealing and shuffling are instant, there are no delays relating to counting chips (for a split pot), and on average the play is faster due to "auto-action" buttons (where the player selects his action before his turn). It is not uncommon for an online poker table to average ninety to one hundred hands per hour.

Another important difference results from the fact that some online poker rooms offer online poker schools that teach the basics and significantly speed up the learning curve for novices. Many online poker rooms also provide free money play so that players may practice these skills in various poker games and limits without the risk of losing real money, and generally offer the hand history of played hands for analysis and discussion using a poker hand converter. People who previously had no way to learn and improve because they had no one to play with now have the ability to learn the game much quicker and gain experience from free-money play.