Planet Reseller at Cebit was an area which was closed for the general public, and focussed on trade-only visitors. You needed a special invitation to enter. This high-traffic area is now located in hall 12, and is recommended to visit, if you are a business person.
UPDATE: The name “Planet Reseller” will no longer be used, and you will NOT need a separate pass as previous years. Anyone with a regular ticket is allowed to access this reseller area.
Below are a few photos of when it is was needed to pre-register as a business visitor. It was free to do it, and the area had separate entrances/exits.