The Postoffice Protocol (POP) is an email receiving protocol. Although simpler than the newer IMAP email receiving protocol, POP continues to garner greater support. POP uses the URI "pop://". Below are addresses of POP servers on which public access is freely given* (each host has their own method of being contacted).
[IANA Port assignment = 110]
* Please note that the hosting "postmaster" must create a primary mailbox address on the POP server, where your email can be received and stored.