Some folks have been running into a problem where they close the chat bar at the bottom of the site and cannot reactivate it. To the best of my knowledge, this is by design. The remote website that controls our chat places a cookie on your browser that tells it not to load on subsequent visits.
If you'd like to reactivate chat at any point, the way to do it is to clear your browser's cache. Here's a decent article on the subject. Note that doing this will clear all of your current session information for any site you're on, forcing you to log back in.
That's the short-term solution. The long-term solution is for me to find a better chat module. Since people want things like alchemists, lore, and scaling racial abilities, though, that will have to wait until I have more time. ;)