On March 26, 2014, blacklist administrator Brielle Bruns announced that the Abusive Hosts Blocking List DNSBLs are to be shut down.

In email to me, she explained:
"After quite a bit of thought and consideration, I've decided that it is time to wind down some of the AHBL's public DNSbl services - specifically the dnsbl, ircbl, and rhsbl. 
We've had a good 11 year run with the lists.  Times have changed -- with the deployment of IPv6 moving full speed ahead, I don't feel that the current implementation of our DNSbl services are suited to the task. 
This doesn't mean that the AHBL is going away - we'll still be around, just focusing our efforts on a mix of other anti-abuse related things and a relaunch of the RHSbl (likely in 2-3 months, possibly sooner). 
I look forward to continuing to work with the community, and appreciate and value the feedback I've received over the years."
As a result, the lists, and, and associated public look up tools are being retired.

I've known Brielle for many years and my interactions with her have been universally positive. Congratulations on a long eleven year run with AHBL, and I hope whatever she works on next is something she finds fun and fulfilling.