Online gambling sites all appear different until you click onto the online casinos that they offer and suddenly several of them look very similar and the reason for this is that very few if any of those online gambling sites actually write their own casino software. Online casino gambling has become very extensive with an online casino often offering hundreds of casino slot games as well as the other gambling games such as roulette or blackjack so the casino software required to support all these casino games has become very specialised so it easier for those casino gambling sites to use one or more of the companies that specialise in casino software. These are not generally names that trip off the tongue; the larger ones being Playtech, NetEnt and Microgaming; but they nevertheless are an important factor in whether or not you enjoy your casino gambling. There are other smaller casino software suppliers that also have some excellent slots such as Amatic Industries and some of the more forward looking online casinos such as All Irish Casino use more than one software supplier leaving the choice of what type of casino game you like to you. Gambling online at an online casino is very dependent on which of the casino software suppliers is in use but the fact that more than one casino uses the same software is not always a bad thing especially when it comes to the progressive jackpot slots as those are often available at several online casinos. Every spin of a jackpot slot contributes a minute amount to the jackpot pool so the more online casinos that are running the slot the more players there are and therefore the quicker the jackpot builds up. This also goes some way to explain why online casinos are very happy when one of their players wins a jackpot as they get all the publicity without any additional cost.