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 ~+~+~+~.