Undoubtedly, the form of cheating that most players fear is collusion. This might be two players at the same table revealing their hole cards to one another via the telephone or Instant Messenger, or just a single player playing two hands in the same game from the same location (using two accounts, two phone lines and two PCs), perhaps raising with one hand and re-raising with another to force other players out of the pot. Indeed, it is theoretically possible to imagine a scenario in which every other player at the table apart from you could actually be sitting in the same Internet cafe!

However, it is important to note that even if you know the hole cards of another player, or have the facility to raise and reraise with two hands in the same game, it still requires a fairly high degree of poker skill to be able to utilise this to defeat the other players at the table. It is quite likely that many poor players might still lose even if they were to cheat, and misjudged attempts at collusion could actually cause some of them to lose more than they would playing ’straight’! Furthermore, it is much less likely that you will come across any cheating at the lower limits. One has to wonder whether an adept collusion team would bother with games lower than say, $5/$10 - if you have made up your mind to cheat, one assumes that you would do so for large enough stakes to make it worthwhile, given the risk of getting caught and potentially having your account closed and bankroll frozen. One would also imagine that short-handed games are more vulnerable to online cardsharps than full ring games, since it is easier to cheat two or three players than eight, and in short-handed play every player is involved in far more pots, so any collusion partnership would be presented with that many more opportunities to cheat.

It is also worth bearing in mind the fact that collusion is not just an online phenomenon - it has been a problem since poker was invented. Just as it is a concern for online cardrooms nowadays, it has also been a problem at some live-action games in the past, with unsuspecting players running into teams of colluders exchanging information about their hands via verbal codes or hand signals.

There are only two ways to combat the cheats: extreme vigilance by the players and security measures from the cardroom. If you suspect that two or more players may be colluding, you have a responsibility both to yourself and to other players to report these suspicions to the cardroom for investigation. At a brick and mortar cardroom, security staff have the advantage of being able to watch the players, and in particular observe how they interact with one another. Although online cardrooms do not have this facility, they do have the important option of being able to go back and scrutinise everyone’s hole cards for any hand that might be deemed worthy of investigation. Furthermore, most online cardrooms claim to possess sophisticated software that can automatically pinpoint other suspicious activities, such as abnormally high win rates. For example, at Paradise Poker the following measures are in place, quoting from an e-mail sent from their support team in the summer of 2002:

Our Security Department makes use of the following preventative measures:
1. Tracking IP address and matching historical playing patterns. This flags and determines if certain players historically play on the same table.
2. Player trapping monitoring. Historical hands are automatically reviewed and if a weak hand was involved with raising and re-raising with multiple players it is flagged and forwarded to security.
3. Strong hand folding. If a player folds a strong hand before the flop such as AQ when another player has AK it is flagged.
4. Any player that reports a suspicious hand, it is thoroughly reviewed by our security dept. Security will also review the historical hands of the players involved. It is this ability to see every player’s entire history that gives us the incredible ability to combat collusion better than a brick and mortar cardroom.

There are also additional automated features that I have declined to mention, given that making such measures public would essentially defeat their purpose … We are under no illusion that in order for us to be successful we need to grow our client base and have positive word of mouth, this could never be accomplished if the games were not conducted in a totally fair and honest environment.

There have been instances in the past where proven colluders have had their accounts frozen, and players whom the cardroom believes may possibly have been colluding (without possessing any concrete proof) are often barred from sitting at the same table together in future. However, there have also undoubtedly been many instances in which colluders have managed to evade detection. It is unlikely that cheating can ever be completely eradicated from poker (either in its online or live-action forms), but if players remain vigilant and report any suspicious activities, thereby helping to police the game themselves, then hopefully any colluders can be identified and barred from the game.