I’m assuming that you haven’t played poker online yet or you are just starting to play online. People around you might advise you to play or not play poker online or “live”
Let's start with a selection of the most heard objections to online poker.

There are basically four categories:
• I can't see who I am playing against.
•  How do I know the site is honest?
•  Can people play together against me?
•  Is it safe to play for real money online?
 
I can't see who I am playing against.
 
…is often heard being said by "live" players, who emphasize that they win mainly because they can "read" the player's tells. (Tells are signals that a player subconsciously gives about the strength of his or her hand).
Obviously there will be less physical tells on players online, since you can’t see your opponents. Online players very seldom “talk” (chat) during hands so that is one more information source you are missing online.
However there definitely are online tells. The most common online “tell” is the time it takes a player to bet. You have to study your opponents before you are able to tell if betting quick or taking a long time to call, means weakness or strength. Some players take a lot of time to bet when they want to lure you in. Or call quickly when they have a flush draw. If you pay attention you can definitely find online “tells”. Just be careful not to confuse the “I really need to go to the restroom” tell with the others.
So there is less emphasize on tells en reads, but that is not necessarily bad though. It just means that your focus should be on the other poker skills like; knowing your odds, your interpretation of the actions (betting patterns) , past information of the player and controlling your emotional state. And the good news is that these skills are easier controlled and developed when you play in a online poker room versus and brick and mortar poker room.  
For example knowing your odds is a lot easier to do when you have an odds page sitting in front of you or a odds program running on your pc, and you will soon remember them if you use them all the time. But this would be considered bad poker ethics or cheating in a live poker room.  

Interpretation of this hand's action is also a lot easier online since you can look back in the chat screen to see who exactly made what bet, call or raise, instead of having to remember it. And you will soon be trained to do this automatically without having to refer to the chat screen. In a real poker room you are not suppose to ask who did what on the last round and will most likely get a wrong answer any way. And as a beginner to remember this might take too much of you mental focus so it overshadows all other skills. It is also easier to see how much someone bets and how much is in the pot. 
When playing in an online poker room you can make notes about players either on paper, on your pc or in some cases in the internet poker software itself. This enables you to see in one look what kind of player you are up against and if you have played against this player before. In a live game taking notes is also bad poker ethics and remembering it for every player might take up to much of you concentration.  

And last but not least when playing online poker it is often a lot easier to control your emotional state since you can control all the factors in your room to suite your focus and relaxation needs. You could play some relaxing music, take up all the space you need on your table, dress how you like, undress if you like , watch a movie to stop you from getting impatient and eat drink and smoke all you like or don't like. And you don't have to look at someone's ugly faces like in poker rooms (trust me there are some ugly poker players out there). So the only thing to put you on a steaming tilt now is bad beats. And most of the before mentioned things are frowned upon in live poker rooms (especially the undressing I have noticed).  
Another "I can't see who I am playing against" comment I have heard a lot is that you could be playing against a world champion or a monkey and have no visual clue. Well if you are playing low to middle limit you don't have to worry too much about world champions but you should definitely be aware of monkeys.
 
How do I know the site is honest?
 
You can't really know if the site is honest, but on the other hand you can't really know if live card rooms are honest. Most sites have some independent random generator reports to show that they are fair, but logic will most likely dictate that most big poker rooms will indeed be fair. Since poker rooms make their money by taking rake from pots instead of making profit if you loose, it is less likely that they will cheat. And since by that very tax system big sites make millions, why would they take the risk of someone finding out they cheat and going public with it and lose all players confidence and go bankrupt. In short nothing is impossible but it is very unlikely.
 
Can people play together against me?
The answer is yes and it is not hard for them to do. They could pick up a phone and tell each other there cards. It happens. Most poker rooms run some kind of software that checks against certain suspicious patterns or people playing from the same IP address. you can off course always mail the sites if you suspect collusion between players (be sure to name the players and the hands). And most of the time (if you motivate your complaint thoroughly) the site will do an investigation. This kind of collusion is easier to do online than when you are playing poker in a live game. But it can also happen in a live game.
Also remember that winning players often see no need in cheating since the risk being banned from a site and their money and account frozen. So the players that are likely to cheat are players that don't play very well. This means that their cheating strategy may likely be questionable if not losing.  
Is it safe to play for real money online?  
To play for real money online is done by depositing money to your account at a online poker room. There are all kind of methods to deposit like; credit card, bank transfer, money order, check, or a debit card. Most sites have very tight security on their deposit methods (or use outside companies to handle that part of the business). But all these methods have some risk in them online as well as in daily other use. We prefer neteller which is a free internet account that works like a credit card except that have to deposit money on it first and there is no credit line. This puts an extra line of defense and in the worst case scenario you only lose what you have deposited on the account. Also you can order a debit card to go with it. This enables you to get to your money almost immediately thru ATM machines world wide. And is a lot easier than getting a check send to you. We will explain more about the deposit methods in future essays.
Here we briefly touched upon some subject that we will write about in more detail in the online poker section. We hoped you enjoyed this summary and it will help you to decide.