Was 55m sell-through. Most people called it a tame or realistic prediction.
Thread also got bumped in December after Sony's announcement of 50m. For some reason many people thought that put the prediction on track. Why didn't it come true? Probably because Black Friday has come to Europe, thus shifting sales from December to November.
Considering the PS4 will probably end 2016 with nearly 54 million sold, that's a pretty good prediction considering it was made a full year ahead of time.
53.4m is the year-end tally. And I am not going to give myself a pat on the back for being off by 1.6m when it seemed like 55m should be easily doable. I didn't make the prediction thread, but I agreed with it.