Thanks for the feedback, you mean like a chat box that would appear on every page or a pop-out window?
The only problem I see with chat is that a lot of people will ask questions etc. in there, which means they wont post instead - this means people who have a similar question wont be able to see the answers.
If people think it is a good idea then it could be quite easily done.
what about a way to message other users? it shows who is online when you look on the left hand side but there is really no what of saying hello to them or asking them a quick question. Just another thought