A Dropbox user received an error message when he tried to share a link to a Dropbox file via IM with a friend. The message was triggered because the content of the file was in violation of the Digital Millennium Copyright Act (DMCA) The error was posted over an icon of an empty file folder:Certain files in this folder can’t be shared due to a takedown request in accordance with the DMCA. The error message set off a mini-panic at the idea of Dropbox peeking into supposedly personal folders.”]
Source: https://nakedsecurity.sophos.com/2014/04/01/dropbox-says-it-isnt-poking-around-in-our-stuff/