It is proper "Wikiquette" (WI-kee-ket) to sign your messages on talk pages. This prevents readers from confusing your posts with messages by other users.
To sign a message, move the cursor to the end of the message, and then with your mouse click on the signature icon () in the toolbar at the top of the edit box. This inserts the signature code (~~~~) where the cursor is. When you save the page, these tilde characters are converted to your signature followed by a date stamp.
You can also type this code in manually with the four tilde characters ~+~+~+~.