I imagine that's where they get the vast majority of their ad-targeting signals, though. They can't show ads based on how much you like the random thoughts of a

I imagine that's where they get the vast majority of their ad-targeting signals, though. They can't show ads based on how much you like the random thoughts of an acquaintance of unknown proximity, they need us to signal our feelings toward fixed commercial targets and sources that can be analyzed reliably for sentiment.