Group Lifecycle dichotomy -Cascade Tree Pattern Depth=1 Depth=2 . Subtree size: The size of sub-cascade .Depth: The depth of invitation .Wiener Index: Average distance between two nodes11 Group Lifecycle Dichotomy – Cascade Tree Pattern •Subtree size: The size of sub-cascade •Depth: The depth of invitation •Wiener Index: Average distance between two nodes Depth=1 Depth=2