There is a big difference between the way people play Texas Hold em online and the way they play in live games. Playing online is fun and can be helpful, but there are some mistakes that you can make online that would be just plain embarrassing in a live game. There are all types of different Texas Hold em players, from extremely tight to very aggressive. Your style may change in varying games, but your personality definitely shines through most of the games you play.
There are all too many aggressive Texas Hold em players online. These are the people that, whether they have good cards or not, raise to extreme amounts or like to push all-in on all or most of the hands. Some of these players will limp into pots, but once they're in - they become extremely aggressive. Others are aggressive by doing these actions even before the flop. Because often when you buy into tournaments online you are only paying $10 or less for $2,000 -$3,000 worth of chips - it's easy to make ludicrous bets and also easier to call them.
There is another type of aggressive player, but this one doesn't quite care about playing cards. They want all the money at the table or none so they can move onto the next table as quickly as possible, moving all of their chips in regardless of the hand or position for every hand. I would call them annoying. They take away from the fun of the game as well as the poker strategy.
There are many players who have figured out one of the tricks to surviving in Texas Hold em online games - sit and wait. Don't play anything because within the first ten minutes of playing a Texas Holdem online tournament, if there are 6,000 people in at the beginning - almost a quarter of them will be gone. They have also realized that they cannot sit back for too long as the blinds will eat them alive and they won't have enough chips to be any kind of a threat to the aggressive players still left in the tournament.
There is an option online to click a button that says post blind and fold. Some people will slip through entire games with this clicked on. They never play any hands and they never call raises. This happens because often times people register hours prior to the tournaments and forget or just end up having something more important to do. These players are easy to spot because you will begin to notice when someone folds every hand they are dealt when the bets are raised. This also happens sometimes because people want to wait until half of the opponents are gone before they begin playing their hands.
Some people, usually new to Texas Hold em online, try to play as they would in a land casino and often get frustrated by the others playing. If you are one of these players, take heed - people play and win with some ridiculous hands online. It's not to say that playing is not fun online; it's just different.
What kind of player are you?