ETA: I was hoping to have some more solid theories at this point re: 'Pending Discussions" but damn if I'm still confused. I have to take off for a work thing but will be back to analyze this later this evening. PLEASE continue to not star and reply... FOR SCIENCE!
So maybe everybody is more on the ball than me and already knows this, but I feel like I've made a small discovery: the grays disappear in Nu Kinja, but are replaced by nothingness. OoooO. (I'm being melodramatic, but they are Very Hidden!)
Here's a screenshot taken from the very, very bottom of Snacktastic's middle class post:
"Pending Discussions" — as selected by Kinja's algorithm, I assume? — don't show up unless you click that link... which, for what it's worth, is ONLY visible after having selected to view "All replies" (not the default, at least not for me).
Down in pending discussions appears to be what would have been the gray pre-tiger. Except it's different now, because I checked and the folks who have posted Pending Discussions don't necessarily correlate with the old grays. In the Nu system, there's no option I can see to "follow for Groupthink," though it appears I can ban per Dweeze's Very Important Research! (Please don't ban people; we do not deserve this power.)
Based on my limited research it looks like the Nu Grays are established by a lack of stars and/or reply comments. Anyone can be a Nu Gray — if no one digs what you say (the Kinja way), then you are dropped into Pending Discussions. I imagine there's also an element of if the OP author follows you at play as well?
Let's do an experiment. Reply to this post, no one star or reply to anyone else.