SuccessFactors Acquires CubeTree

San Mateo-based SuccessFactors said Monday that it has acquired Redwood City-based CubeTree, in a deal worth $50M. SuccessFactors said the definitive agreement is worth $20M in SuccessFactors stock plus a contingent cash payment three years from closing. CubeTree develops social networking software for businesses, and was venture backed by Interwest Partners, Trinity Ventures, and Mitch Kapor.