I must disagree, theymos. A P2P system does not have servers. Instead it has a network of nodes that each as as important as any other node. A email server interacts with clients by hosting and/or routing all of the mail for the clients. In order for email to be p2p there would need to be no servers, only a network in which every node hosted a share of the required workload and a share of the disk space. The benefits of this system is that if a single node went down the network could have enough redundancy for there to be no issue. In a server based system like current email if the server goes down then there is no way for the network to function. Of course, storage of messages would need to be encrypted like any P2P storage network.

Thank you, Nefario. I will look into that i2p email program. Perhaps it will be what I am looking for.