There are many ways in which you can cheat with online games, the most popular way is to have more than one account, this enables the person to gain extra power over other players.
We actively monitor every player's IP, check every IP to see whether or not it is a proxy and collect other data in order to prevent players from opening more than one account. We spend a lot of time and money on trying to combat this type of cheating, we are not always successful and with the nature of the Internet and technology there will always be ways players will find a way around to create multiple account.
One of the other most popular ways of cheating is feeding, this is when one player deliberately sets up an account for another player to come and take assets. Again, we actively log every action within the game so we can look through accounts for this type of behaviour. It is not fair on any of the players for another player to have a distinct advantage.
There is also exploiting game code, this is done when somebody notices the game or the code is not react in the way it should and giving a player and advantage. It is completely against the rules of the game to take advantage of any exploit. An example of a game exploit would be when you are practising something and you are getting more than you should. But not limited to purchasing things, perhaps you found a way you could travel for nothing.
We monitor every aspect of the game in order to prevent any cheating or exploiting getting out of hand before it is dealt with, however it will happen not every player wishes to play fairly.