Over the past one and a half years, Stack Overflow has lost around 50% of its traffic. This decline is similarly reflected in site usage, with approximately a 50% decrease in the number of questions and answers, as well as the number of votes these posts receive.
The charts below show the usage represented by a moving average of 49 days.
What happened?
As alluded to by comments here already, a long coming death.
Will probably go down as a marker of the darker side of tech culture, which, not coincidentally (?) manifested at time when the field was most confused as to what constitutes its actual discipline and whether it was an engineering field at all.