PCWorld has the story of a Dropbox breach that saw user email addresses compromised. While the breach was rather minor, with no passwords being leaked, Dropbox also revealed a more serious issue that no amount of security can stop:
The company also found that usernames and passwords that had been stolen from other websites were used to access “a small number of Dropbox accounts.” Hackers commonly try username and password combinations from breaches on other web services in hopes people use the same combination, a common security problem.
Come on people, don’t use the same password on every site. If you do, you’re asking for trouble.