My wife didn’t really pay attention to the reddit controversy and frankly didn’t really care. She is about as casual ad you can get and even She has noticed a very steep decline in the quality of content shared on reddit. She barely uses it anymore. Now this is a person who doesn’t notice when her adblocker is on or not. If she noticed this, i can guarantee she is not alone.

Digg, ... don’t fail in a day

It depends on precisely what you mean by "fail" and how strictly you take "day", but Digg did lose 50% of its traffic within 30 days (and it never recovered).