I would like to create a "spam list" with some of the case subjects. My first idea was to create a custom object, with a field (set) where I can add the different "spam" subjects, a couple of methods, one to add subjects (a button in the "case" detail) and other to remove subjects from a list. And then create a trigger, which before insert/update a case, check the list, and close the case if the current subject is already on the list.
I don't really need more than one object, so I have been reading that maybe it's better to use a custom setting. but I have no idea.
Which option would be better?