For native traffic, I'm aware that brands drive up the CPC's this time of the year, but that should just equate to less traffic. I'm wondering what could be the causes of conversion rate % tanking.
Well depends on your offer really ... put yourself in the consumer shoes ... is whatever you are promoting something that they would be interested in right now? Or would it be crowded out by all the other things on people's minds ... holidays, family, gifts, stress, finishing up work, travel, social events, etc.
There's an old saying in mail order-- "Santa Claus is a thief." Historically direct response offers unrelated to Christmas have always tanked in December...but January was always the best mail order month of the year because people had Christmas cash to spend, and were simply bored and stuck indoors due to winter weather.
people are more-so buying products for other people, rather than themselves.