Fraudulent behavior on the part of online casinos has been documented. The most commonly reported behaviors are refusal to pay withdrawals or cheating software. An online casino with multiple confirmed cases of fraudulent behavior is often called a rogue casino by the online casino player community. One commonly reported behavior related to refusal to pay withdrawals is the refusal to pay withdrawals promptly. A rogue casino may intentionally delay a withdrawal in hopes that the player will continue gambling with the money in the account and lose it all back.

Some casino software has been mathematically proven to cheat, such as Elka System/Oyster Gaming and Casino Bar. Screen shots from the back office of an older brand of software indicated the odds could be adjusted by the operator. Many casino gambling portals and player forums maintain blacklists of rogue casinos. While some carry more authority than others, most blacklists constitute individual webmaster and player opinions rather than anything official from any type of regulating body.

Common fraudulent behavior from online casinos players includes the signing up for multiple casino accounts using different identities in order to claim a bonus offer multiple times. Another form of fraudulent behavior might be the use of a graphics editing software like Adobe Photoshop to create a false winning slot machine game screenshot in an attempt to tell the casino they hit a jackpot and didn't get paid for it. Online casinos usually lock the player accounts for these people. Some observers believe that online casinos share fraudulent player blacklists.

There are two basic game options available: Software-based games and flash-based games. Today, more and more online casinos provide both but there are advantages and disadvantages to each one.

Flash-based games don't require any software or any long download. It does however means that every time you wish to play you will need to enter the casino website log in and download the Flash game (which doesn't take long at all) to your browser. The games will be a little slower and the graphics will not be as smooth as in the download version but it has the advantage of being able to play on any computer with an Internet connection – all you need is your user name and password. Casino Software plays an important role in the selection of our preferred casinos. We focus on the major online casino software brands.

This is actually casino software that includes a wide variety of games, which must be downloaded to your computer before playing. The download itself can take up to a half an hour because the software contains all the games, graphics and casino operating system that are needed in order to play in the casino. The only disadvantage that this way of playing has, except its size and initial download speed, is the fact that this restricts the player and enables him to play only on computers on which the software is installed. This option is best suited to people who will be playing on only one computer.

The advantages are that this software already has everything you need to play each and every game the casino offers and there are no additional downloads or waiting time. The graphics and game speed are superior in this mode of play which makes the games much smoother and enjoyable.

Bonus hunting (also known as bonus bagging or bonus whoring) is a type of advantage gambling where turning a profit from casino, sportsbook and poker room bonus situations is mathematically possible. For example, the house edge in blackjack is roughly 0.5%. In the example above, $5000 in wagering with a house edge of 0.5% will result in an expected loss of $25. Since the player received a $100 signup bonus, after subtracting the expected loss of $25, the player has an expected profit of $75. Online casinos offer players signup bonuses as incentives to play. These are usually one-off bonuses for signing up to the casino and opening an account. The terms and conditions attached to each bonus vary but share two common features:

Wagering requirements prevent players from withdrawing the bonus money immediately after receiving it. Before the bonus money can be withdrawn the player must wager a certain amount of money on unrestricted games. The wagering can be spread out over many bets. To meet a $2000 wagering requirement, a player could make 1000 $2 bets on blackjack, provided blackjack is not a restricted game. Games like blackjack and video poker have a low house advantage. The house advantage for blackjack is ~0.5%. So in the example above, by playing $2000 worth of blackjack with a house advantage of 0.5%, a player is, expected to lose $10 in total. But the expected value is an average value and may be less than the actual value. Risk of ruin is an important topic that comes into play.

Assuming that the player only loses an amount close to the expected loss, and the bonus awarded to the player after meeting this wagering requirement is greater than $10 then the player profits. The process is mathematically calculated. Bad luck could cause a player to lose more than $10 playing blackjack in this situation. The run of luck is subject to variance and follows a normal distribution. By taking advantage of 'free' bet promotions, users can back the event, and then lay the event on a betting exchange, at similar or same odds, thus ensuring that their 'free' bet is not a bet at all, instead more like a financial trade. No matter the outcome, it is possible to calculate both the possible outcomes before the sporting event has started. By inputting the odds, the bet calculator then tells you what amount to bet, to ensure that whether the bet wins or loses, the return are the same.