Facebook/google data mining

I saw this post: https://imgur.com/gallery/jrv03 suggesting some scope on Fb/google data collection. No idea if it's underestimated, but I did find it a bit interesting that you could request a download of your own data to get some idea of some data they've stored.

I'd be curious what you guys think about this, if any of it was surprising, if you think it's only the tip of the iceberg, and how big of a problem do you think it is?