"At that point, he could dictate the rules and the rules were that it was off the record, " says Martha Joynt Kumar, professor of political science at Towson University and author of Managing the President's Message: The White House Communication Operation.

BBC: Woodrow Wilson's odd early press conferences

Earlier in the session, Alex Salmond and Sir John Elvidge, Scotland's top civil servant, gave evidence into civil service co-operation and communication.

BBC: Scottish Affairs Committee

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WSJ: Blindfold Brackets 2013: Official Rules

Social media opens up new pathways of communication between a business and its customer base and provides a forum for co-operation and co-creation - one that can produce both small, iterative improvements and large breakthrough innovations.

BBC: Business

"A combination of flawed management information and poor communication with applicants and staff mean that G4S senior management had no idea how badly wrong their operation was going until it was too late to retrieve it, " the report said.

WSJ: Social Media

At present, although New York's black leaders privately admit that they now have better communication with the police on drug problems, they say that this has not turned into any broader co-operation.

ECONOMIST: First safety, then civility