Hi lrock! Thank you for your interest in this topic. I think that the “laws of envy” apply to virtual networks in much the same way as in real life. Since envy results from social comparison it can clearly affect engagement on social media platforms, where comparison processes are inevitable (especially when they are triggered by monetary gratification). However, there are no simple answers to your question and (to date) only few scientific studies investigating envy in social media. One differential aspect that researchers at the University of Michigan and the University of Leuven observed is: active versus passive use (see http://psycnet.apa.org/doiLanding?doi=10.1037%2Fxge0000057). Whereas passive use of social networks (simply browsing posts of others) increased feelings of envy, active use (posting and commenting) had no such effect.
For now, I wouldn’t say that envy is the (only) driving force. There are too many other social and individual factors that impact feelings and behaviours in social networks. Concerning money and emotions GREED is another issue worth considering. Maybe the topic of my next post…