Wikileaks got the blame for putting a US embassy cable regarding Zimbabwe into the public domain. They were soundly condemned by the media and various pundits for endangering Morgan Tsvangirai and the potential for some semblance of democracy in Zimbabwe. As it happens, Wikileaks did not choose to release the cable into the public domain and publish it. It was the Guardian newspaper which made the decision.
UPDATE: Here’s Glenn Greenwald’s piece on the issue.