There are basically four types of online gambling sites on the Internet today. Perhaps the most popular form of online gambling are the free online lotteries where you can play by choosing numbers for free at 'free' online lottery sites. Another type of lottery is the state lotteries controlled by states within specific international country jurisdictions where one can buy lottery tickets online (usually state lotteries such as the Swedish and German lotteries).
Second, there are Sportsbooks and sports gambling and race books where you can place online bets on the outcome of sports games and/or races and which rank as possibly the most popular form of online gambling. As far as customer advantage goes, gambling with a sportsbook or race book provides the customer or bettor with a certain amount of confidence as results are public information right after the games. This may possibly explain the popularity of this type of online gambling.
The last and fourth type of online gambling site is the electronic stock-trading sites. These are not technically considered gambling but when one looks closely, they can be categorized as such. Belonging to this group are the investment games and fantasy stock exchange games.
Online casino gaming sites offer both instant online play in the form of Flash (Macromedia) and/or Java games where no software download is required or play with the online casinos's softwares which must be downloaded. For any of these, a connection to the Internet is required. Today the stunning graphics and sounds available to players with download software make the few minutes of downloading no more an unwanted affair, rather it is an experience to even non-players to witness the ever-increasing special effects (such as male and female dealer voice and casino background sounds) provided by some of these online casinos.