Games that are played in land-based, conventional casinos are known as "brick and mortar" (B&M) casinos games, while those that are played through the Internet casino sites are called online casino games. According to the Christiansen Capitol Advisors, there were about 1,400 online casinos in 2000, raking in a revenue of approximately $2.2 billion. By 2004, the number of online gambling sites, including online casinos, was estimated at 53,000.

The most common type of games offered by online casinos normally include blackjack, roulette, baccarat, craps, pai gow poker, video poker, and slot machines. Most websites provide users with options to play for fun or to play for real money. Some sites may or may not require you to sign up for a username before playing online, and most services are free, but you may need to pay if youre playing for real money.

Online casinos are divided on the basis of gaming interface: No download or Web-based and download-based interface. Web-based interface allows you to play directly on the website using consoles such as Macromedia Flash, Macromedia Shockwave, or Java. Download-based interface requires you to download a specific software program, install it on your system, and connect it to the service provider via the Internet. However, some websites may offer both types of interface according to user preference.

Wager Works, Microgaming, Playtech and Cryptologic are the main providers of software for online casinos. Most major online casinos, such as River Belle, Aztec Riches, Crazy Vegas, King Solomons, etc., purchase their casino game programs from these companies in order to maximize reliability, performance, and functionality.