It depends on what kind of account and server you use have and the kind of your new account and server to be used.
If it's a POP account where new e-mails are batch downloaded to your computer, you don't realy need to transfert them as they are residing on your computer.
In your e-mail client, you just create a new account OR change your current account to the credentials of your new one.
The American woodworker forum is a web based forum.
Unless it can also be accessed from a e-mail client or forum browser using the SNTP protocol, you have to copy the messages one by one. Mozilla Thunderbird can be used as a forum client if the server allow SNTP access.
In all other cases, it realy depends on both providers. Some allow a mass transfert, some don't. BOTH must allow mass transfert if you want to transfert all messages in one go.
Electro
December 2013