Facebook is the world’s largest treasure trove of this data. Every day billions of people give the company huge amounts of information about their lives and dreams.
This isn’t a problem when the data are used ethically — like when a company shows you an ad for a pair of sunglasses you recently searched for.
However, it matters a lot when the data are used maliciously — segmenting society into disconnected echo chambers, and custom-crafting misleading messages to manipulate individuals’ opinions and actions.
That’s exactly what Facebook allowed to happen.

Source: Facebook is killing democracy with its personality profiling data – Salon.com
Think of the political propaganda posters your “friends” share into your news feed. These propaganda posters are not just innocent little posts from friends; they are typically designed by professional propagandists who are using this data to craft messages designed to hit your emotions and get you to adopt their agenda.
Seeing that FB stock is up about $3.50 today indicates the incredible power that Facebook and Mark Zuckerburg have to rule the world. In spite of all the negative publicity, their share price is now going up. FB is viewed as unstoppable. Chilling.