Can you dig into (1) a bit more? Agree that most people are consumers not producers - but FB cleverly and incessantly worked towards making the most hardened consumer into a producer (Like being the first incarnation thereof). Half that site's audience visits every day. They like brand pages and friend's posts. They disclose location when they upload photos.

All of this is low-friction data production unlike the review example you use above (most people are terrible at writing original content unless absolutely required to do so).