Online slots can be classified into three broad groups. The first group is 3 Reel Slots, slotxo also known as Classic Slots. These slots have three reels and usually include symbols reminiscent of the earliest mechanical slot machines like fruit symbols or bars. The Video Slots group is the most widespread. They have 5 reels and are characterized by animation and sound effects and other fancier features. The Progressive Slots can have either 3 reels or 5 reels. They differ from the earlier groups in the nature of the jackpot. In 3 Reel Slots and Video Slots the amount of the jackpot remains fixed and is determined by the payout table. In Progressive Slots each wager adds to the jackpot amount, which keeps growing till it is hit.

Slots neither have the low house edges that games like blackjack and video poker offer nor do they require an element of skill. Yet they are more popular than both blackjack and video poker put together. In fact they are by far the most popular online casino games. The popularity largely lies in the life changing payouts, particularly in progressive jackpots. It is enhanced by the magic of the special effects and the bonus features that online slots routinely offer.

Microgaming – The popularity of online slots can be judged by the proportion of these games in the suite of each online gaming software provider. Microgaming offers a total of 350 games out of which 229 are slots games. In percent terms 65% are slots games. The breakup of the slots games is as follows. 65 are 3 reel slots, 152 are video slots and 12 have been classified as other slots. Out of the 229 slots 16 have progressive jackpots.

Wizard Gaming is a new online gaming software provider. It offers only slots games. There are 23 slots games on offer out of which 4 are 3 reel slots and 19 are video slots. 2 of the video slots have progressive jackpots.

Cryptologic offers a total of 137 games out of which 96 are slots games. In percent terms 70% are slots games. The breakup of the slots games is as follows. 8 are 3 reel slots, 84 are video slots (including Marvel branded slots) and 4 have been classified as casual slots. Cryptologic slots have a high proportion of progressive jackpots with 34 out of the 96 slots having progressive jackpots.

Playtech offers a total of 97 games out of which 43 are slots games. In percent terms 44% are slots games. The breakup of the slots games is as follows. 17 are 3 reel slots and 26 are video slots. Out of the 43 slots 13 have progressive jackpots.

Real Time Gaming offers a total of about 110 games out of which 73 are slots games. In percent terms 66% are slots games. The breakup of the slots games is as follows. 11 are 3 reel slots and 62 are video slots. Out of the 73 slots 12 have progressive jackpots.

Vegas Technology offers a total of about 86 games out of which 57 are slots games. In percent terms 66% are slots games. The slot games include both 3 reel slots and video slots. Out of the 57 slots 7 have progressive jackpots.

New games are added frequently and hence these numbers will change in the future. But the slot games will continue to hold dominance. In fact since most of the new casino games are slot games, therefore the proportion of slot games will increase. The slot games considered above do not include proprietary slots that are offered in some online casinos. If that is taken into account the number of slots games will increase.