70% – 80% of the profits in the industry come from online slot machines.

In the past, slot machines used to attributed to 70% of the profits in the land-based casino industry, but in recent years, slots have come to represent 85%. In some countries, it accounted for an even greater percentage of the profits.
Internet slot machines can duplicate the traditional casino experience on the Internet. Here’s it works:
Each machine has a number of spinning reels (3 reels or 5 reels) of which each has a number of “stops”, some are blank and some have symbols. Each stop has a probability of coming up on any given spin such as a bar symbol that’s programmed to show up with a probability of 1/10, but it’s not necessarily the same as the other such as the cherry symbol might have a probability of 1/20.
The designers of these games calculate the probabilities of combinations of these symbols and program the payoffs in such a way that the house has a mathematical edge over the player.
An online casino relies on the laws of large numbers to make profit from hundreds of machines being played by hundreds of gamblers for hundreds of spins per hour. Thus, they don’t mind if you win but in the long run, the casino always wins more on its slot machines than it pays out. Besides, when think about it, if players never won, they’d never play, and that would be disastrous for them.

You can’t count cards in online blackjack.

As we already know that online casino also offer option of playing some table games via Webcam with real live dealers and actual decks of cards. Among them, Blackjack is probably the most popular.
Counting cards is not hard to do as you just need to assign a value to the low cards and a value to the high cards in the deck. Follow by moving your count up and down as the cards are dealt. It is a heuristic method for keeping up with the ratio of high cards to low cards that are left in the deck as you have a better chance of being dealt a “natural” or a blackjack when there are many high cards. However, this only works where the deck doesn’t get shuffled on every hand.
But a lot of blackjack players might not know that live dealer blackjack casinos use automatic shuffling machines to shuffle after every hand. No exceptions. This routine makes the house edge as close to 0 at some online casino sites.
Do a little research into the rules variations of the sites where you play to see what the house edge is so that you find the best odds.