The underline indicates you had an entry in the optional "Your Email" box of the message editor.
When you enter text in the "Your Email" box, a hyper-link is created in the message. Point your mouse at the link, and check the bottom left area of your browser window (Explorer), and you'll see the target of the link.
If you leave the box empty (or remove the default text from the box), your name will no longer be underlined. Existing messages can be edited to remove the link by removing the contents of the "Your Email" box.
Scoring disabled. You must be logged in to score posts.