I'm all for busting some balls, especially if we're talking Dropbox. But shit like this happens all the time, and it's not like by busting some balls here we're going to improve the situation broadly speaking.
It's really absurd to expect that your information will actually be safeguarded by some entity that isn't you. As soon as you give any data to anyone, it's gone. You should pretty much assume it's public and get on with your life. Did ya'll catch that blog post up yesterday from the kid who deleted the USERS table at his job, because he was developing against a production database and running queries against it by hand? Experience has led me to believe that's the situation at like all things, everywhere, all the time. Ass clowns emailing around spreadsheets with user data; people getting malware installed on their Windows shit and entire infrastructure's data being compromised. It's a joke. Let's just always remember that while we're busting balls. But if you value your data, don't give it to anybody, ever.
