On October 22, David Oranchak — long-time Zodiac community member and Zodiac Killer cipher expert — presented an excellent review and analysis of the current state of the Zodiac Killer ciphers at the 2015 Cryptologic History Symposium. The talk, entitled The Zodiac Ciphers: What do we know? And when can we stop trying to solve them?, ties together all the great work done by David — as documented on his website zodiackillerciphers.com — and other valuable contributors in the Zodiac community, most notably at zodiackillersite.com in recent years.
Congratulations, to Dave, on a job well done. If these ciphers will ever be solved, it's going to be due to a combination of effectively communicating what's truly known and sparking the interest of someone who has the requisite knowledge and, honestly, the luck to make the right educated guesses in terms of what the killer actually did. Perhaps that interest was ignited long ago, in one of us who is already in the community. Or, perhaps, the spark's existence lies down a yet-to-be-traveled path (yes, I'm mixing my metaphors). Either way, this presentation is a valuable contribution to the advancement of the case. I think it's safe to say that all of us who have a serious interest in seeing this case solved appreciate the time and effort David invested into making this happen.
If you'd like to know what other types of talks were given at the Cryptologic History Symposium, have a look at the agenda. You can also read a discussion of David's presentation — from the time of acceptance onward — in this thread.
Update: I added the video of Dave's presentation above. Dave also added some comments regarding the symposium on his website. Below are the two videos he mentions. The first is a short news clip which Dan Olson — chief of the FBI’s Cryptanalysis and Racketeering Records Unit — showed. The second is a recording of Dave's fellow presenter Klaus Schmeh, who discusses instances of unsolved crimes that include the existence of at least one unsolved cryptogram. The talk includes some rather humorous recreations of historical events.
FBI Codebreaker Segment