The Politics, Philosophy, News, and Society subforum under Off Topic is looking pretty abysmal. Why are so few people using it? Just a year or so ago it was bustling with new threads and old ones were still ripe with discussion. What's changed?
I don't really think there's anything else to tell you. People stop posting there, hence the activity is declining. People move on and that's perhaps why it's no longer the bustling section you used to know. Can't really give you a definitive answer as to why.
What's up with PPNS?