Chat can be annotated in the same was as users (see Annotating users). The ability to add annotations to chat was added because it is useful for doing Computer-Mediated Communication research, where frequently one assigns codes to each chat message such as speech-acts from a speech act taxonomy like Bach and Harnish (1979).
You can bring up the chat window by clicking "Show chat" in the avatars panel (Tools-->Show avatars). If that button is disabled (i.e. not clickable) it means that the selected group of avatars have no chat messages in the data.
Note that this does not mean that the group of avatars chatted with each other. VWTk has no way of figuring out who chatted with whom. The "Show chat" button simply indicates whether or not at least one person in the selected group of avatars has uttered any messages.
The chat window contains chat messages sorted by time. The first column is time when the chat messages was uttered, second is the username (i.e. name of the avatar or nickname) and the third is the chat message. None of these columns is editable, renameable or removable. You can add more columns and rename and remove those. Right click (Ctrl+click) on the Mac to do that.
A feature of the chat window is that whenever you select one or more chat messages, the symbol corresponding to it gets highlighted in the main visualization. If you scroll down the table using the keyboard you can see the pattern of chats as they occurred in space and time.
As with user annotations, annotations made to chat are reflected in the visualization in real time. Hover over the chat symbols to see the annotations.
