How to sign comments
On talk pages, it is proper etiquette to sign and date your messages. This is normally handled automatically by the software, but to do it manually, add four tildes (~~~~) to the end of your message. When you save the page, these will be converted to your signature plus the current date and time. The default "sig" is your username, but you can customize it in your preferences menu). To include your signature only (usually not a good idea), use three tildes instead (~~~). Signing your posts prevents readers from getting your messages confused with those by other users; with the date/time stamp included, other users can follow the flow of the conversation.
Read more: Wikipedia:Signatures