IP Logging
When you create a note, Dead Drop stores your IP address with it. We do this so that, if someone uses Dead Drop to send malicious notes, we have a chance of banning them. Dead drop is intended as a secure means of sharing sensitive information with others, such as passwords or key files. But like much of the internet, it's open to misuse, and storing the IP address of the note creator gives us a chance to block people who are misusing it if we receive complaints.
We also store the IP address of the reader of the note, once it's been read, for the same reason.
The logged IP addresses last only as long as the note they're logged with. Notes are permanently deleted within 24-48 hours of their creation, regardless of whether they've been read or not. When the note goes, the logged IP address goes with it.