Hi,
Little discourse feedback, after login in the first time, I remove myself from the 2 automated threads Introduced yourself and Welcome to MPU Talk!. However now, I keep having the notifications displayed and no way to remove them…
In my Notifications panel, the Dismiss All button is disabled 
The top message is a personal message, rather than a thread. The second one can be unfollowed by opening the thread, and then changing “Tracking” or “Watching” to Normal.
As I removed myself from the mesages, when I click on the notification I get a nice :
“Sorry, you don’t have access to that topic!” 
I can’t untrack them.
Oh, just realised right now : the Introduced Yourself notification has gone… I did nothing.