> But if the resulting model doesn't contain information about individuals, how does this help targeting individuals for the campaign?
I don't know exactly what they were modeling, but from the published reports, it sounds like they were trying to predict big 5 personality characteristics (conscientousness, neuroticism, openness, extraversion, agreeableness) from FB profile data (e.g. likes, dislikes, bio, post content, etc.). So in that case, the model would contain weights that measure the strength of relationship between characteristics like "likes punk rock music" and "openness". That description really only literally applies to a linear model - but nonlinear models are, for these purposes, the same.
I don't know exactly what they were modeling, but from the published reports, it sounds like they were trying to predict big 5 personality characteristics (conscientousness, neuroticism, openness, extraversion, agreeableness) from FB profile data (e.g. likes, dislikes, bio, post content, etc.). So in that case, the model would contain weights that measure the strength of relationship between characteristics like "likes punk rock music" and "openness". That description really only literally applies to a linear model - but nonlinear models are, for these purposes, the same.