Don't subscribe to the thread. There is an option you can set to stop it happening automatically and you can unsubscribe from all using one of the links in your notification emails.
I don't want to be doing this every time I post on a foreign thread. Is there a way I could bypass it?
You can edit your existing subscriptions here: http://forums.digitalpoint.com/subscription.php?folderid=0
Follow this for a permanent solution http://forums.digitalpoint.com/profile.php?do=editoptions. Don't forget to unsubscribe from the old threads.