In my opinion the most important aspects of the new diplomacy is multilateral diplomacy, where more than two states are involved in negotiations, and the public diplomacy-soft power the citizens as well as the media play a greater role.
Before in the “old diplomacy” non-state actors, such as NGOs, did not make part of the negotiations process, nowadays, with the new diplomacy, the diplomacy agenda has become much richer.
In multilateral diplomacy, the fact that more than two states are involved in a negotiation can facilitate the whole process, for instances, states have different points of view, plus the non-state actors can create pressure in the decision making as well as the media and public opinion.
Issues such as environment and human rights can ”move” a lot of people such as international organizations, in this case Greenpeace and the Amnesty International respectively, and other singular activists and all that can weigh a lot in the final decision.
Also in the multilateral relationships all states are equal when negotiating, there they are all at the same level, there are no powerful and weak states in this situation. However power difference can still exist. While states may have one vote each, the more powerful states usually dominate the weaker states. They can use bilateral aid relations which weaker states to secure their votes, for instance. They also benefit from the exchanging of experiences and information, the more states the better in a sense that the discussion will involve variety of opinions.
However is worth mentioning that multilateral diplomacy can also create more conflicts and tensions between the states involved.
Overall, even if multilateral diplomacy can create awkward situations between states such as in extreme cases with physical assault and the policies changing can be delayed in comparison to bilateral negotiations, on the other hand, it can create more opportunities for other less favourable states, as they will take equal part as the other powerful states in the negotiations, and also it makes possible for the public to demonstrate their opinions, as well as it makes the indirect politics possible.