Have you register on some website? If you have, then it's probably not the only one. There are several services available on the network that require the user to perform some record. Several also are applications designed to capture these passwords to use unlawfully.
The MultiKey is an essential app for anyone who uses the Internet and want more security. If you always use the same password for everything, know that this practice is not recommended by experts in Internet security.
Through the application you can generate different passwords, mixing between a word (encrypted) and a key. Thus, helping you to generate different passwords for a simpler form.