June: The PM button is to send a Private Message to any board member; useful if you don't have an email address, or if the member prefers to keep address private. Your email address will display in the PM, but you won't see the receipent's email address.
And it it
ALWAYS proper to start a new message; we do tend to "hijack" threads
and sometimes the origial topic gets lost.
For unsubscribing, at the top of each page is a link "My Controls". Go to it, and on the left hand side, about half way down is "Subscriptions". Click on "View Topics" and choose which topics you would like to unsubscribe from (yeah, my grammer ain't none too good), and do the same with "View Forums". I'd suspicion that you've acidentaly click on "Track this topic" or "Subscribe to this forum" at the bottom of one of the thread pages.
I haven't typed that much in some time.