Message icons allow you to specify a small icon to accompany your posting, which is used to convey the emotion or content of a post at a glance.
The default is set to "no icon." Icon choices include several smilies, as well as other objects such as an arrow, a light bulb, a question mark, a thumbs-up and thumbs-down sign.
If you use a message icon on a post that starts a new thread, the icon appears to the left of your thread's subject title in the summary screen. If you use a message icon in a reply post, the icon appears to the immediate left of your own subject header.