Problem
In my prediction community list are old obsolete prediction communities. I would like to cancel my membership in these.
Solution
The prediction community will only disappear from there when you cancelled your membership or when the administrator deletes it.
To cancel your membership in a prediction community, you have to first go to this community. You can do so via "My profile" - "My communities". From within you can then go to "My profile" - "Cancel membership" to delete your access to it.
If you are the administrator, you can delete a community in the admin area via "Delete prediction community". Only then can you also delete your account.