Social media is an excellent supplemental tool in the practice and study of public diplomacy because it holds strategic potential for enhancing communication tactics, promoting policy objectives, and providing evaluation mechanisms. Social media provides a new platform from which diplomats can benefit, provided it is a forum used effectively. It should not, however, replace or dominate the larger practice of public diplomacy. A foundation of PD is the people and the relationships that are affected by the policies it promotes. The negative side effects of utilizing this unique form of communication must be accounted for at all stages of planning. If the main aim of public diplomacy is to inform, engage, influence, empower, and understand foreign publics on behalf of an international actor, then social media offers an innovative opportunity along the road to achieving that goal.
I recently presented my thesis research at the Santa Barbara Global Studies Conference, where I had the opportunity to solicit constructive suggestions for where to go next. I have uploaded my presentation and recorded my lecture here to welcome your feedback.
Kelsey Suemnicht 
Digital diplomacy would be something of a buzzword, a neologism. My main criticism is that it highlights the value of a medium (transmission mode that uses discrete values rather than a continuous, or analog, spectrum of values) or tool (closely linked to information technology), rather than a strategy. (BTW: U.S. State Department refers to “complementing traditional foreign policy tools with newly innovated and adapted instruments of statecraft that fully leverage the networks, technologies, and demographics of our interconnected world” as 21st Century Statecraft, eDiplomacy is just a part of it).
In that sense, I agree more with the concept of public diplomacy, which I think refers to a target or an objective (making known, patent, or manifest, the interests and relations with other nations), and the actor or group that it seeks to establish a relationship with (including groups of people involved in certain issues or living in certain places).
In other words, I think the focus should not be primarily in the medium, but in how messages (communication strategies and tactics) are structured / tailored. Furthermore, the target audience is the one that will define both (the messege and the means of contact, influence and persuasion to be used; be them traditional or novel).
Moreover, even if “social media holds strategic potential for enhancing communication tactics”, there is no guarantee that it will. Even if it has this potential, it does not imply that it will be used that way. I think there are high hopes talk of a “natural culture of sharing, collaboration and two way engagement” (as if it were something spontaneous, something that regularly and usually happens). The reality is that more often than not social media is used only for broadcasting (transmitting, sending, spreading, promulgating information), and not necessarily for communication (understood as interaction or engagement betwwen social actors).