They are basically the same rules that you have in the casinos and poker rooms across the states. Roberts Rules apply in most instances and most of the online poker gaming sites use the same rules.
The only variations that you will find will be in ‘specialty games’. That would be any game where the poker site has started a game with variations, which is rare. And you would notice that most of the new games that do have a different set of rules are mostly involved in regards to time.
Poker has been around for thousands of years without change and most likely will be around, pretty much the same for thousands of yeas longer. Actual changes to the game usually come in the home game arena. You will see wild cards, specialty games such as Southern Cross, 7-21, Chase the Queen and such as that. Although sometimes fun for a change of pace, they are not considered poker games by real poker players.
You can find Roberts Rules of Poker online just by typing in the name Roberts Rules of Poker (there are other Roberts Rules and you don’t need those) and it will pop up right there on page one of the search engine. The latest version is number 11.
As a matter of fact, you will find that the online poker gaming sites use the Roberts Rules more stringently than do the casinos. A casino will have some rules that you will not find in Roberts and their rules are the ones that will apply. After all, it is their casino and you are a guest. Sometimes it helps if you read their rules prior to playing to save embarrassment at the table.
One thing is monumentally different online. Since you are online, you cannot see anyone, hear anyone, or be able to ‘judge’ other player’s strengths and weaknesses. That is a large part of playing the game. Also, players who play online have a tendency to play like they are on TV. If you watch the game on the tube, you know what I mean. When there isn’t much money involved, there is a tendency to bet larger than what you would normally do in order to take down pots.