What PGP is, and why You should use it:
PGP, aka ‘Pretty Good Privacy’ is an encryption program that provides cryptographic privacy and authentication for data communication. PGP can be used to send messages confidentially. Messages encrypted using public PGP key can only be decrypted using related private PGP key which should be kept secret!
Real life example of PGP usage:
Scenario – User wants to send Vendor a private message which could only be read by him/her. User asks Vendor for their public PGP key, then copies and pastes it to a dedicated PGP software. User writes the desired message and clicks encrypt. PGP software outputs encrypted message. User sends encrypted message to the Vendor thru email, forum, or market. Vendor then decrypts the message using his private PGP key in a similar manner as User encrypted it.