Global Suppression Lists

Global Suppression List.
Pander File.
Screamers List.

Whatever you call it, it’s the list of email addresses you suppress from every mailing.
If you’re an ESP, this is the list of people who you never, ever want to send email to – and I’m talking about ESP-wide global suppression lists here, not the suppression lists maintained per-customer.
Global suppression lists are a vital tool to have, as it’s the only way you can comply with requests like “Never mail me again.” – and failing to comply with those will lead to, at best, irritation, yelling and blocking, and at worst legal action.
But it’s only the right tool for suppressing mail in a few cases. One obvious one is when someone specifically requests no more mail, ever, through your system. Another is when there’s a technical reason (you never want to send mail to autoresponders, for instance), or a legal reason (pending litigation, or an incompatibility between the mail you send and a specific jurisdiction).
And there are a very few people who just cause way too much support overhead when you send them email – that’s the origin of the term screamer list, I’m sure.
But it’s not what you should be reaching for in response to spam complaints, even heated ones, or feedback loop hits. A spam complaint is a sign that your customer is probably doing something wrong, and that this recipient doesn’t want that customers mail. A feedback loop hit says that this recipient doesn’t want that customers mail (and, statistically may indicate that your customer has a problem).
Neither of them is a sign that the recipient doesn’t want mail from any of your customers. You definitely wouldn’t want one of your customers sending spam to cause mail from all of your customers to be blocked – so why would you let a complaint about one of your customers block mail to that recipient from all your customers?
(We’ve occasionally come across ESPs who have preemptively blocked all mail to addresses @wordtothewise.com, for no clear reason. When our clients discover that their ESPs are silently discarding our attempts to subscribe to their mailing lists it doesn’t do much for that ESPs reputation in our clients’ eyes.)
And whatever you do, don’t respond to a spam complaint telling them you’ve added them to a global suppression list. That says several things, to an already annoyed person. It tells them that you’ve just broken their subscriptions, past or future, to your other customers. And by “fixing” the spam problem for this one recipent in this way it suggests that you’re not actually going to do anything to deal with the customer they’re complaining about. Nothing about this can end well.
Instead, tell them that you’ll make sure they don’t receive any further mail from that customer, and that you’ll talk with the customer and take action that you deem appropriate. (And then do that).
P.S. Does anyone know the origin or etymology of the term “pander file”?