Online casinos generally offer odds and payback percentages that are comparable to land-based casinos. Some online casinos claim higher payback percentages for slot machine games, and some publish payout percentage audits on their websites. Assuming that the online casino is using an appropriately programmed random number generator, table games like blackjack have an established house edge. The payout percentage for these games are established by the rules of the game.
Reliability and trust issues are commonplace and often questioned. Many online casinos lease or purchase their software from well-known companies like Wager Works, Microgaming, Realtime Gaming, Playtech and Cryptologic in an attempt to "piggyback" their reputation on the software manufacturer's credibility. These software companies either use or claim to use random number generators to ensure that the numbers, cards or dice appear randomly.
Online casino types
Online casinos can be divided into three groups based on their interface: web-based casinos, download-based casinos, and more recently live casinos. Some casinos offer multiple interfaces.
Web-based online casinos
Web-based online casinos are websites where users may play casino games without downloading software to the local computer. Games are mainly represented in the browser plugins Macromedia Flash, Macromedia Shockwave, or Java and require browser support for these plugins. Also, bandwidth is needed since all graphics, sounds and animations are loaded through the web via the plugin. Some online casinos also allow gameplay through a plain HTML interface.
Download-based online casinos
Download-based online casinos require the download of the software client in order to play and wager on the casino games offered. The online casino software connects to the casino service provider and handles contact without browser support. Download-based online casinos generally run faster than web-based online casinos since the graphics and sound programs are located within the software client, rather than having to be loaded from the Internet. On the other hand, the initial download and installation of a download-based online casino client does take time. As with any download from the Internet, the risk of the program containing malware does exist.
Live-based casinos
Live-based casino gaming is a way to interface with a real world casino while playing online. Recent advancments in communication technology now allow land-based casinos to open a real-time window via the web for players to game tables in an interactive, live environment. With live gaming players can see, hear, and interact with live dealers at tables in brick and mortar casinos worldwide.
Signup bonuses
Many online casinos offer signup bonuses to new players making their first deposit. These bonuses normally match a percentage of the player's deposit with a dollar maximum, and almost all online casino signup bonuses require a minimum amount of wagering before allowing a cash out. Gameplay at specific casino games might be excluded from the wagering requirement calculation.
A fictional signup bonus offer follows as an example:
The online casino offers new players a deposit matching bonus of 100%, up to $100
The player must wager 25 times the total amount of the deposit plus the bonus before withdrawing
Wagers on baccarat, craps, roulette, and sic bo do not count towards meeting wagering requirements
For this particular example, this would mean that a player depositing $100 would start with $200 in his account. The player must make $5000 ($200 × 25) in wagers before being allowed to make a withdrawal.
Advantage play in casino signup 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, the player has an expected profit of $75.
Advantage players who use bonus offers for an expected profit are often called "bonus hunters", "bonus abusers", "bonus baggers", "bonus whores" and "casino scalpers". Some online casinos have restrictions regarding "the spirit of the bonus offer" which they sometimes use as a deterrent to what they consider "bonus abuse".
A player who wishes to do this at a large number of online casinos must be careful. Some casinos are rogues (see below) and do not pay. Others have terms and conditions that are not favorable to the player, such as most bonuses that are restricted to slots.