https://zerobin.stanik.us – Leave private messages and small attachments for others. The URL contains the encryption key. Only those having the URL can decrypt the message. The encryption key is not sent to the server.
Answers for security questions, e.g. "What was your first pet's name?"
Appropiate where verification takes place over the telephone or in situations where unlimited guessing is impossible. The issue with answering security questions truthfully is perhaps your pet's name can be found by searching Facebook.
Desktop, laptop, website passwords
Appropiate where manually typing a large number of guesses is impractical or repeated login failures would be noticed and access subsequently blocked.
When something absolutely, positively needs to remain private use one of these. An army of computers relentlessly trying requires a lifetime of guesses, a giganormous budget and a bit of luck.
Appropiate when the items being protect might likely be copied to a specialized computer system for password cracking. Encrypted hard drives, usb drives, zip/rar archives, etc.
Appropiate when using a password manager so there would be little need to commit these to memory or manually enter them except in unusual circumstances.
Use when copy and paste is generally an option, e.g. password manager.