POP
- Downloads email messages to local device, then removes messages from server (unless configured otherwise in program settings)
- 'SENT' messages stored in mail program only, so devices connecting to the same email account can't see messages sent from (i.e. laptop would only see messages sent from laptop; phone would only see messages sent from phone; etc.)
- Folders are local to device, and are not shared with other devices connecting to the account
IMAP
- Syncs messages in mail client with server
- 'SENT' messages folder syncs with server, so all devices connecting would see all sent mail (keep in mind, some devices like iPhones may not sync sent mail by default; please refer to Apple documentation for your device)
- Folder structure is synced with the server, so all devices would utilize the same custom folders within the Inbox