This paper employs three block-modeling and partitioning methodologies: matrix joining process, CONCOR and permutation with partition through matrix joining process, and CONCOR and permutation with partition based on sign change for partitioning a virtual community into sub-communities. We also design a robust check to measure and compare the performance of those three methods in terms of error rates. Our empirical results reveal that (1) CONCOR plus permutation would favor the situation where there are only two subgroups. (2) The variable percentage of missing is not a determinant for error rates. (3) The error rates are not much affected by matrix size. (4) Maximizing X_C^2 value as the criterion function for matrix joining process might be too stringent since it considers both ties sent to and received from every pair of actors in the evaluated subgroup.

This paper employs three block-modeling and partitioning methodologies: matrix joining process, CONCOR and permutation with partition through matrix joining process, and CONCOR and permutation with partition based on sign change for partitioning a virtual community into sub-communities. We also design a robust check to measure and compare the performance of those three methods in terms of error rates. Our empirical results reveal that (1) CONCOR plus permutation would favor the situation where there are only two subgroups. (2) The variable percentage of missing is not a determinant for error rates. (3) The error rates are not much affected by matrix size. (4) Maximizing X_C^2 value as the criterion function for matrix joining process might be too stringent since it considers both ties sent to and received from every pair of actors in the evaluated subgroup.

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