The number of Social Network Sites (SNS) on Web 2.0 sites has been growing rapidly in recent years. This study analyzes data from three SNS in Taiwan. Several important measures available on Google Analytics are identified through interviews with the founders of the SNS and their daily data are collected. After removing outliers, correlation among measures and multiple regressions, analysis provides rationales for identifying several common users' behavior patterns. One of the case companies is further divided into member and non-member users, and into before and after a business model change. The statistical results for these two comparisons demonstrate the significant connections between users' behavior on SNS and the data collected from Google Analytics.