Sorry, Michael but your reply confuses me.
Lets just focus on IMAP because that is the type of account that is set up on the server and on my client (both laptop & iphone).
My main email client sits on my laptop. Since this client has to handle incoming messages from multiple accounts on multiple servers I believe that I have to set up the Spamsieve Spam folder ON MY MAC (and I have).
Since this is a folder residing on my mac and not on the server it leaves the spam mail in the Inbox on the server (as there is no Spam folder on the IMAP server).
If I were to make a Spam folder on the IMAP server and set up Spamsieve to move the spam mail to a folder called Spam on the serve, all the incoming mail from the verious accounts would have to first move all mail to the one account with Spam folder residing on it before it process the rules. That doesn’t seem very efficient. Or am I confused about how Spamseive works on the clients.