Comments are broken. I don’t know what’s wrong, but I suspect it might be something where the comment IDs are nearing 2 million. Long running blog + lots of spammers = big numeric IDs. Or it could be some problem with the database size.
I’ll poke at it more in detail when I have some time tomorrow or over the weekend. For now, if you really want to comment, I might recommend following me on Google+ where I’ve been cross-posting about the blog posts.
And, if anyone has any experience with WordPress and this particular error, let me know. The symptom is that submitting a comment seems to not do anything. I’ve disabled all the plugins and that did nothing. My preview plugin lets you preview the comment, but shows a comment ID that seems rather odd given that no new comments are coming in.
If you have any ideas, email me: email@example.com