"Archives" are where old or unused comments are put, so they don't take up room on the main talk page when they are not needed. This doesn't mean that the conversation is over - in fact, you can start it back up again so long as you follow these rules:
• Copy and Paste over - find the conversation on this page you want to bring back to the talk page; edit the section ("edit" button at the →); click in the box and press CTRL+A and then CTRL+C • Post to the current talkpage - open up the current talk page by clicking this link; press the "+" button at the very top; click in the big box and press CTRL+V; type a good header and edit summary, and save.
