Archiving is used on talk and project pages (never on articles) to keep them from getting too long to be useful, while retaining older discussions in case somebody should need to refer to them.

The preferred method for archiving a talk page is to copy the older content to a series of subpages. This can be performed either by hand or automatically by a bot.

You may find these templates helpful:

• ((Archive banner|state=uncollapsed)) (full page width banner)
• ((Archives|auto=yes|search=yes)) (float right box)