Table 1.

Properties of the Twitter subgraph.

Properties of nodes
Avg. degree	$\overline{d}=\mathbb{E}\left\{d_{\mathrm{i}}\left(X\right)\right\}$	123.55
variance of out-degree	Var{do(X)}	30,096.16
variance of in-degree	Var{di(X)}	24,338.66
covariance	Cov{di(X), do(X)}	14,226.32
Properties of friends and followers
Friend’s avg. out-degree	$\mathbb{E}\left\{d_{\mathrm{o}}\left(Y\right)\right\}$	367.14
Friend’s avg. in-degree	$\mathbb{E}\left\{d_{\mathrm{i}}\left(Y\right)\right\}$	238.68
Follower’s avg. in-degree	$\mathbb{E}\left\{d_{\mathrm{i}}\left(Z\right)\right\}$	320.54
Follower’s avg. out-degree	$\mathbb{E}\left\{d_{\mathrm{o}}\left(Z\right)\right\}$	238.68