As reported on Spamtacular and on SORBS' website:
"ANNOUNCEMENT: Possible SORBS Closure... It comes with great sadness that I have to announce the imminent closure of SORBS. The University of Queensland have decided not to honor their agreement with myself and SORBS and terminate the hosting contract.
I have been involved with institutions such as Griffith University trying to arrange alternative hosting for SORBS, but as of 12 noon, 22nd June 2009 no hosting has been acquired and therefore I have been forced in to this announcement. SORBS is officially "For Sale" should anyone wish to purchase it as a going concern, but failing that and failing to find alternative hosting for a 42RU rack in the Brisbane area of Queensland Australia SORBS will be shutting down permanently in 28 days, on 20th July 2009 at 12 noon.
This announcement will be replicated on the main SORBS website at the earliest opportunity. [...] -- Michelle Sullivan (Previously known as Matthew Sullivan)"
(Note that the quote from SORBS ends above.) My recommendation at this time is to cease using the various SORBS DNSBLs until and unless stable hosting is obtained by the list operator. I've already noticed intermittent issues accessing the SORBS website, and if their hosting is in flux it's likely to impact their ability to maintain the master database online. The net result is that you could have timeouts, delaying inbound mail, or you could have false positive blocking issues where mirrors of SORBS are caching data no longer intended to be published by the list operator.
Note that my recommendations are aimed only at those already known to use SORBS. I've strongly recommended against using SORBS in the past, due to what I believe to be significant false positive issues. But, obviously, email administrators have the right to decide what mail they wish to accept, based on whatever criteria they wish to follow.
8/03/2009 Update: SORBS operator Michelle Sullivan said the following on a public mailing list recently: "SORBS is not closing. SORBS has received 3 credible offers for the purchase of SORBS, one of which was not interested in continuing SORBS but obtaining the IP and spamtraps. SORBS will not be accepting the latter offer."