I started without very strong beliefs about blackmail, and over the course of the discussion I think mostly just gained more fleshed-out models of blackmail. I still lean towards "Blackmail is bad, should probably be illegal" and think most of the arguments to the contrary seemed optimistic or naive.
But the arguments to the contrary did also deepen my understanding of what things you might want to accomplish with blackmail, such as:
I don't think blackmail is a very useful way to go about that, but the underlying goals there seem important and I can think about them more clearly.
While it's not the traditional blue vs. red politics, it seems very political to me.
Even when the debate is unlikely to have an effect on the dejure legality of blackmail it's not certain that there aren't practical consequences.
People generally don't want other people to blackmail them and as a result they do have a stake in promoting social norms according to which blackmail should be shunned.
The debate was started by Hanson who's a person who already advises projects that try to get around the law to enable people to make money with information that couldn't be monetized previously.
It's not politics in disguise, but it's hard to discuss rationally for similar reasons. Politics is hard-mode for rationality because it is a subcategory of identity and morals. The moral rightness of a concrete action seems likely to trigger all of the same self-justification that any politics discussion will, albeit along different lines. Making this problem plausibly worse is that the discussion of morality here cannot be as easily tied to disagreements about predicted outcomes as those that occur in politics.
I did not detect any consensus, except insofar as people mostly kept their previous position.
I found it useful for two reasons: first, it clarified my position on the comparison case of gossip; second, it expanded the regulation of elites into a general consideration, a topic with which I am otherwise much concerned.
The thrust of the blackmail argument was that there are no central reasons to punish it over punishing gossip, with which I agree. This is because I also despise gossip, which I sort-of-knew but it hadn't snapped into clarity before.
I remain sympathetic to the punishment of elites argument; I am slowly considering how much of a hit I would be willing to take in order that the powerful take a bigger one.