Mean degree of each vertex's neighbors in a graph
MeanNeighborDegree[g]
MeanNeighborDegree[g, "In"]
MeanNeighborDegree[g, "Out"]
MeanNeighborDegree[{v -> w, …}, …]
Part[VertexList[g], Ordering[MeanNeighborDegree[g]]]
→ VertexList[g]MeanNeighborDegree[{1 -> 2, 3 -> 1, 3 -> 2, 2 -> 3, 2 -> 4, 3 -> 4}]
→ {4, 3, 3, 4}