Definition: A Blacklist collects known sources of spam. Email traffic then can be filtered against a blacklist to remove spam.
If an Internet service provider provides this service to a spammer and does not take action after a warning by the blacklist's administrators, all email traffic -- also by legitimate users -- from this provider is blocked. This usually creates anger among the provider's non-offending users, which will force the service provider to take action against the spammer.
Alternate Spellings: Black list
Getting rid of unsolicited email.