I used to think Pinterest was simple. Pin consistently. Stay in your niche. Repeat forever. That’s what everyone said, right? And you may have kinda followed it without questioning it much. Pinterest recently shared research from its engineering blog that gives a hint about how content ranking might work. Turns out, showing the same type of content to users over and over, even if they clearly like that topic, actually makes them leave the app faster. Their session time drops. They come back...