Maybe he's using POP3 instead of IMAP? (ie downloading all the email to a local archive) Thunderbird and other clients still support that, and you can still se

Maybe he's using POP3 instead of IMAP? (ie downloading all the email to a local archive) Thunderbird and other clients still support that, and you can still search & tag messages within your local email archives. It also means if your email server is hacked, they won't get your entire email history - unless your local machine gets hacked, of course.