So does my solution work for you?
I subscribed to this thread with the 'notify me by email feature when it is updated' and it was sent to my gmails spam box
- that may be true, because this email is fully automated. Gmail also as other services often block automated emails by default. You may "teach" the Gmail marking this email as "Not spam" so hopefully next time it could recognize it correctly.
This happens not only with miniBB.com... with other websites and softwares, too. I often register at other forums and I need to check bulk/spam folders to get an activation key or something like this.
That's way miniBB provides a possibility to register straight-away, with no email check :-)