The placement of smiley icons tells you the approximate number of people in each direction and how alert they are. In order to avoid cluttering up the image the number of smileys displayed is only a rough indication of the number of people. If there is one person in the room then you see one smiley. If there are several people then you see two smileys. If there's a big crowd of people then you'd see three smileys, but no more.
If people in a room have been active recently then the smiley icon used to represent them is made to blink. The dns-com-awns-visual package updates its user-activity information roughly every minute and this also updates the image indicating the movements of people between rooms and changes in their levels of activity.
To the right of the image is a region of text detailing the room name and the names of users in that room. If you move the cursor over the darker region of the image then the text area is updated with details related to the room under your cursor. If the cursor is not over the image then the details for the room at the centre of the image are displayed.