This is for setting up a chat room. Once you select this, an entry box and a submit button will appear below the existing contents, for posting new messages.

 

Note that this is a performance hog, since the browser needs to communicate with the QDL server every 10 seconds to fetch the updated contents, so that it can pick up any new messages that have been posted. So once you're done with a chat room, you should change the data type back to HTML, so that you can browse through the messages without bogging down your machine, and without putting an unnecessary load on the QDL server.