>When you post on twitter, you can be rewarded with engagement and attention and even the possibility of growing your own brand and following. All at no monetary cost to you.

Yes we call that "being paid in exposure" and outside of Silicon Valley it's widely recognized as a scam.

Also bear in mind that content and engagement serves the purpose of driving ad revenue and creating a monetizable social graph, so it's less a "reward" and more "unpaid labor."