The Network Abuse Clearinghouse, A.K.A. abuse.net, is a public database that tracks the contact information of various sending domains. In a nutshell, abuse.net helps forward complaints and abusive activity to network managers, and in turn, these network managers can remedy the situation at the source.
To be clear, abuse.net is not a blacklist, it’s simply a contact database that catalogues who to report abusive behavior to. Publishing an abuse.net DNS record using your email address, something like [email protected], just tells the internet that the complaint reports will land in the right hands.
Publishing your abuse.net record makes it easier for someone to contact the sender, or the email service provider of the sender, to report abuse before it causes deliverability issues.
You can learn more at Network Abuse Clearinghouse.