All poker players can be divided into four groups. All these types of players have their own techniques which can be very useful under certain circumstances.
There are at least two main attributes for each of these types.
Depending on the number of hands the player plays with the players can be either tight or loose. Tight players play few hands and loose players play with a lot of hands.
If the player is aggressive (raises and bluffs) or passive (calls other players bets).
Loose-Aggressive
Loose-aggressive player is the weakest player especially in online poker game. The main feature of such a player is that he raises every time after the flop. In a real casino such a strategy will allow to win only small pots, but in online casinos they will be only a flop. Sharks are often attracted by such players. The sharks are fine with letting these players have 10 small pots; they are after the three large pots which will eventually break this player. To avoid such results it is better for such players to change tables from time to time. For example, every 50 hands.
Loose-Passive
They are no more stronger than the first group. These players can only make money in a game with a lot of wild players and generally have to depend on luck to have a successful poker session. Their strategy is to call the bets of other players no matter how strong their hands are. Such players can stay in the game longer than anybody else, but they will never be able to beat the house edge.
Tight-Passive
What allows players of this type to win is other players who play the game wrong. The main weak point is that it is very easy to see and notice such players. Such players never bluff. This player is more likely to call the bets of other players or to make small bets. They fold if they have a bad hand.
Tight-Aggressive
This is the best type among all others. These players will only see a flop with a decent hand and will then take a shot at the pot after the flop with a bet. Poker Types.

Internet Poker Game Rules > Poker Types