There has been a change in how you use the Chat feature. Please read below:
How do I use Chat?
You can participate in the chatroom directly from any page of the network, by accessing the Chat bar at the bottom of the page. From the Chat bar, you can see the number of members signed into Chat, pop the Chat window up, pop the Chat window out into a new window, and toggle your status as online or disconnected from Chat.
When you sign in to a network with the Chat feature on it, you will automatically appear as "online" in the chatroom.
In the right column, a list of members currently in the chatroom appears.
Clicking on their profile photo pops up a dialogue that allows you to view their profile on the network or initiate a private chat with them. When the member accepts, the two of you will be placed in your own separate chatroom.
You can navigate back to the main chatroom at any time by clicking the Main tab.