playing with cryptography...

[David Picón Álvarez]

With a certificate of this kind you can sign e-mail and decrypt e-mail 
encrypted to you on the basis of S/MIME, which is a different protocol from 
OpenPGP and incompatible with it. The pros of it is that it is supported by 
mainstream MUAs, Outlook Express and MS Outlook, and the Web of Trust issues 
are handled in a less flexible but simpler way (lots of money to become 
accredited).

--David.