Accordnig to NJABL’s website, they’re shutting down effective immediately:
March 1, 2013: NJABL is in the process of being shut down. The DNSBL zones have been emptied. After “the Internet” has had some time to remove NJABL from server configs, the NS’s will be pointed off into unallocated space to hopefully make the shutdown obvious to those who were slower to notice.
If you have NJABL listed in your MDaemon or SecurityGateway configuration, you should probably remove it immediately. MDaemon’s SpamAssassin automatically uses NJABL as well, but as long as you have automatic updates enabled no action is required, SpamAssassin will be disabling NJABL per bug 6913.
To NJABL’s operators: Thanks for all your time and efforts, it was appreciated!