What exactly is the State Department?
The U.S. Department of State (a.k.a the State Department) is the government organization responsible for managing America's relationships with other countries.There are a gagillion bureaus and offices within the State Department in D.C., but there are also people from here in 265 locations around the world. Some of them work in embassies and consulates all over the place, where they work to promote U.S. economic, political, ideological and humanitarian interests.
John Kerry is the Secretary of State, which means he's the head of the State Department. He's fourth in line to the U.S. presidency, is Obama's principal advisor about everything to do with foreign policy, and represents America abroad.
What the State Department doesn't do is create laws and decide issues that only concern America and no other countries (that's Congress) and physically wage war (that's the military.) But they do basically everything else!
What exactly is Public Diplomacy?
First of all, diplomacy is the practice of conducting negotiations between governments. When America's government talks to Sweden's government, that's diplomacy.
Public diplomacy, however, is the practice of communicating with the people who live in different countries around the world. A lot of America's interests depend, not just on other governments, but on other societies. We want people in other countries to be entrepreneurial and innovative, to create jobs and build strong economies and enter into trade agreements with us. We want people in other countries to have a favorable impression of us so they will want to cooperate with us and will see eye to eye on global issues such as climate change and human rights. We don't want people to attack us, and we want people to understand why they shouldn't be attacking each other either. It's better for America if a young man growing up abroad becomes a small businessman rather than joining an extremist group, for example. Etc, etc, etc.
Public diplomacy can take many forms. The Facebook page "Democracy Challenge" is run by the State Department and engages people from around the world in conversations about democracy. This month, the U.S. embassy in Turkey organized a Hackathon for local university students to learn about social entrepreneurship. Earlier this spring, the embassy in Skopje hosted a Fashion Show for young Macedonian designers to promote the textile industry there. Films, magazines, books, TV, technology and more influence the way the rest of the world views America. Cultural exchange programs expose people to American culture and help promote America's message and interests to inform and influence people.
The place I'm working deals with public diplomacy as it relates to 46 countries in Europe and Eurasia.