GoodNews is equipped with an import feature for subscriber lists via CSV (Comma Separated Value) files.
(Screenshot: GoodNews Management Interface - Subscribers Import)
Formatting the CSV files
The CSV file you'd like to import needs to have 2 separated values. The first column holds the email address, the second one the full name of the subscriber. If you don't have a full name available, it's recommended to use the email address as full name value.
"email@example.com","Darth Vader" "firstname.lastname@example.org","Leia Organa" "email@example.com","Luke Skywalker" "firstname.lastname@example.org","Darth Maul" "email@example.com","Chewie" "firstname.lastname@example.org","Han Solo"