Your signature is a small text box which can feature plain text, quotations and even text links to other web sites. Often active members of a forum wish to publicise there own websites when posting and the signature proves a great way to do this.
Below is an example of a signature:
"Good warriors cause others to come to them, and do not go to others"
Simply fill in or update your signature code via your profile page and you will find that it will be displayed underneath all of your forum posts. Please note that if you change your signature the changes will take affect over all your posts old and new.
If you run or administrate your own website and especially if that site is related in some way to the forum topic, it is strongly recommended that you give the signature a try.