TL;DR Using IMAP is like syncing each account. If it's 'Read' in one account it's marked as 'Read' in all, same goes for delete or send or whatever. The more b

TL;DR Using IMAP is like syncing each account. If it's 'Read' in one account it's marked as 'Read' in all, same goes for delete or send or whatever. The more basic approach 'POP' downloads a copy, no syncing.