Almost all online poker variants have different table positions that every player should know before joining a poker game. These positions include the blinds and the button. Position defines where a player sits relative to the dealer and whether you'll be first or last to act in a round of betting.
In online poker, dealing is done automatically by the computer. One of the players is still defined as the dealer (a sort of symbolic dealer), or a player "in the button". This role of the button is in transition and moves to a different player each poker hand. The order of the poker game is set according to the position of the button.
Being in the button is the most desired online poker position in some games like Texas Hold'em, since after the flop, the person on the button will always be the last to act in each round of betting.
Early - The early position is consisted of players sitting in the three seats to the left of the dealer. This is the worst position in poker, because you are the first to bet without knowing how the other online poker players will choose to play the round. Poker players in the early position should limit themselves to betting only on premium hands, because they have no idea as to the player action of the other poker players.
Middle - The middle position is made of the players after the early position players. In middle table position, players can see the action of the poker players in early position before they have to act. This is why they don’t have to limit betting to premium hands, but they still need to be cautious.
Players in middle position are the best candidates to try and bluff in online poker, because they have seen some hands and have a few hands in front of them.
Late - This table position is made of the last players - the dealer and the players sitting to the right of him. These poker players have the advantage of having seen most of their opponents already act. The very last player to act has best online poker table position on the table. The advantage for the players in this position is because:
Before you make a move in the game think about your current table position, if you are in the early position, be more careful and only bet great hands. In middle position, you can bet on medium hands. The late position has an advantage for betting but don’t over-estimate that advantage.
Michael Orwell - Editorial Board