https://hbr.org/2017/03/whats-the-value-of-a-like
1. Whether liking a brand makes people more likely to purchase it
no
2. Whether people's likes affect their friends'purchasing
no
3. Wheather liking affects things other than purchasing
no
4. Wheather boosting likes by paying Facebook to display branded content in followers' news feed increase the chance of meaningful behavior change
yes
