The US State Department, which has the slogan "Diplomacy in Action, spent $690,000 ($US630,000) to try and "buy fans" in social media, the agency's Inspector General said in a report.
The State Department's Bureau of International Information Programs spent the money to increase its "likes" count from 2011 to March 2013, the Washington Examiner reported.
"Many in the bureau criticize the advertising campaigns as 'buying fans' who may have once clicked on an ad or 'liked' a photo but have no real interest in the topic and have never engaged further," the inspector general reported.
The State Department's Facebook page likes increased during the spending from 100,000 to more than 2 million and to 450,000 on Facebook's foreign-language pages.
Despite the increase, the IG said the spending did not reach the bureau's target audience, mainly older and more influential people. Only about 2 per cent of the department's fans engaged with the pages by liking, sharing or commenting.
In September last year, Facebook changed its approach to users' news feeds, and the costly "fan" campaigns became much less valuable, the IG reported. The bureau now must pay for sponsored ads to keep its content visible even to people who have already liked its pages.
"The absence of a Department wide PD [public diplomacy] strategy tying resources to priorities directly affects IIP's work. Fundamental questions remain unresolved. What is the proper balance between engaging young people and marginalized groups versus elites and opinion leaders?" the IG said.
The report also stated that the bureau did not have a social media strategy. Various State Department bureaus had over 150 social media accounts that were uncoordinated and often overlapping.