This article is from the PGP FAQ, by Jeff Licquia firstname.lastname@example.org with numerous contributions by others.
Public Key Servers exist for the purpose of making your public key
available in a common database where everybody can have access to it
for the purpose of encrypting messages to you. While a number of key
servers exist, it is only necessary to send your key to one of them.
The key server will take care of the job of sending your key to all
other known servers.
Very recently, the number of keys reported on the key servers passed