"Oh, yeah, I know a cool trick, but y'all have to wait until tomorrow to find out what it is."
"Look! It's a way to evaluate SQL expressions with a select with a from! Oh, you already knew about it?"
I have nothing against sharing knowledge, especially when seeing someone else do something that can be done better. But just leaving daily breadcrumbs to remind people you're the guy that teaches random trivia feels like attention seeking.