A Blueprint is a design or technical drawing of a Holobuilding that has been created in the HoloBuilding Editor.
By owning a Blueprint, you can create, edit, position, and place the corresponding HoloBuilding on your property.
If you are the designer of, or if you own the full rights to, a Blueprint you will be able to sell it to other players. Those players will then have the right to place the corresponding HoloBuilding on their Properties inside Earth 2.