A chat room enables a faster paced and more indepth discussion of the game, by the nature of forums the slow pace can hinder useful information being passed especially with others posting useless comments.
The forums today are always the same questions. A chat would enable rookies to learn faster and also allow those who care more about the game discuss it real time. A chat is to compliment the tools we already have and most games have already taken this step, I know hattrick has multiple chatrooms on different servers. If it is something you don't like or don't want to join then the forums will still be here with the same "Which player is better?" "What offense should I run" threads.
I know there is a good chunk of players that sit at their computers watching their games might as well chat between everyone doing the same thing.
FC
Superfly Guy: The forum Post I linked has the instructions to a fully registered permanent chat room. All it needs it more activity and it could possibly develop into something fun. Step by Step ;)