Essays on the Economics of Electronic Commerce

ACKNOWLEDGEMENTS Time flies! Four years went away like a snap of the fingers. Yet, it has been a happy, fruitful journey, with outstanding education from which I will continuously derive benefits and cheerful memories that I will always cherish in my life time. Along this journey, many people and friends stood by my side, providing me guidance, help, and supports. I would like to take the chance to acknowledge them for helping me during my doctoral work. I would especially like to thank Han Zhang, my advisor, for his guidance and commitment. It has been a pleasure to work with him, whose patience and support helped me overcome many crisis situations and finish this dissertation. I am also extremely grateful for the advice, help, and generosity I received from Haizheng Li, my advisor during my study in the master's program in economics. He leaded me to develop independent thinking and continually stimulated my scientific thinking. It has been fun to study and work together! Finally, I would like to thank my family for their supports and patience. Without them, I will not be possible to achieve the great milestone.