Networks have structures, and structures influence the way individuals and networks behave. (Rheingold 2012, “Net Smart”, p. 191)
social media == social network?
Mark Granovetter
- TikTok - Hailey
- Tumblr - Nellie
In 1906 Vilfredo Pareto noted 80% of the land in Italy was owned by 20% of the population.
90% of everything is crap
⇐ fat head: 80% of sales in top 20% (e.g., Barnes & Nobles)
⇒ long tail: 20% of sales are in lesser 80% (e.g., Amazon)
In an overdispersed regime, identifying transmission events (someone infected someone else) is more important than identifying infected individuals.
It’s not intellectually satisfying, but because of the overdispersion and its stochasticity, there may not be an explanation beyond that the worst-hit regions, at least initially, simply had a few unlucky early super-spreading events. (Tufekci 2020)
part of your happiness might depend on people you never met (Rheingold 2012, “Net Smart”, p. 198)
Happiness is “clumpy” in social networks, why?
- random
- homophilly (e.g., happy people like each other)
- confounding variable (e.g., wealthy people are friends and happier)
- causal/contagious
Longitudinal statistical models [of 4739 people from 1983–2003] suggest that clusters of happiness result from the spread of happiness and not just a tendency for people to associate with [the] similar
A friend who lives within a mile … and who becomes happy increases the probability that a person is happy by 25%. (FowlerChristakis 2008)
Similar for co-resident spouses, siblings within a mile, and next door neighbors. No effects for coworkers.
The value of (broadcast) network is proportional to the number of viewers: N.
Content is king.
The value of (telecommunications) networks is proportional to the number of potential transactions: N2. It’s quadratic.
(Actually, n*((n-1)/2), but don’t worry about that.)
The value of (social) networks is proportional to the number of possible groups/affiliations: 2N. It’s exponential.
| 2 | 8 | 16 | |
|---|---|---|---|
| Sarnoff (N) | |||
| Metcalfe (N2) | |||
| Reed (2N) |
| 2 | 8 | 16 | |
|---|---|---|---|
| Sarnoff (N) | 2 | 8 | 16 |
| Metcalfe (N2) | 4 | 64 | 256 |
| Reed (2N) | 4 | 256 | 65536 |
mnemonic??

these businesses depend on network effects… [which] involves raising lots of capital and moving quickly to dominate a new market, even when … [they] may not know how they are going to make money in the long term.
The goal for Lyft and Uber—and for all the entrepreneurs being urged to blitzscale—should be to make their companies more sustainable, not just more explosive; more equitable, not more extractive. (OReilly 2019)

Networked individuals have partial membership in multiple networks and rely less on permanent memberships in settled groups. (RainieWellman 2012, “Network”, p. 12)
How could we use this to help people?
Write down the most complex or confusing topic that you would like more clarity on.
Social capital
The benefits of networks of trust and expectations of reciprocity.
But is it a “public good” as Rheingold (2012, p. 220) claims?