It stands for a development policy in which all interact. The logo is to be a trademark of development policy's great involvement in Expo 2000, and be seen everywhere by visitors and non-visitors alike. The latter will see it on the exhibition's Internet site. Those who go to Hanover will come across it around the exhibition grounds and in the electronic information system for visitors. That helps orientation and stimulates curiosity.
Interest can grow out of curiosity, and interest can create understanding.