SecureDrop is an open-source whistleblower support system, originally written by Aaron Swartz and now run by the Freedom of the Press Foundation. The first instance of this system was named StrongBox and is being run by the New Yorker. To further add to the naming confusion, Aaron Swartz called the system DeadDrop when he wrote the code.
I participated in a detailed security audit of the StrongBox implementation, along with some great researchers from the University of Washington and Jake Applebaum. The problems we found were largely procedural, and things that the Freedom of the Press Foundation are working to fix.
Freedom of the Press Foundation is not running any instances of SecureDrop. It has about a half dozen major news organization lined up, and will be helping them install their own starting the first week of November. So hopefully any would-be whistleblowers will soon have their choice of news organizations to securely communicate with.