Hey.
What is the deal with PGP signatures?
They are numeric proof that a particular person created a message and that is hasn't been altered.
How can I use them?
You can use them to supply proof that a message hasn't been altered from the author's originally intended message.
PGP messages, how do they work?
They use asymmetric encryption to allow an individual to create a message that can only be read by the individual who has access to the private key.