Smileys are small graphics that have the purpose of expressing feelings and thus underlining the written opinion. If you chat every once in a while, you're probably familiar with smileys. Some "standard strings" are automatically converted to smileys. Just put your head to the side and with a bit of imagination you should be able to recognize a face.
If you don't want to use the graphic smileys in a post, you can use the 'Disable smileys' option when composing a post. Then it will be ;) not converted into a graphic smiley, but remains as ;) stand in the text!
