It has actually been 6 hours for the last couple of weeks. elizabeth is right, Pubski is unaffected.
I intend to end the experiment this week, once I am back on home internet. It hasn't had an obvious effect on activity (https://hubski.com/stats), but I'd like people to give feedback if they've noticed anything.
It's not a blanket 12 (6) hour waiting period. I follow tacocat, and see all of his comments immediately, so does anyone else that follows him, or that he responds to. If people don't like it, that's ok. It's an experiment. I still feel that people are unnecessarily hostile to each other in comment threads, and that the medium is partly to blame. I'm still ok with experimenting with the medium.