51.com (hereinafter referred to 51), established in August 2005, is the largest social network service provider in China. 51 is jointly invested by Sequoia Capital, SIG Asia Investments (SAI), Giant Interactive, Intel Capital, Redpoint Ventures and other renowned international enterprises and venture funds. 51 is committed to offer its users stable services to store their personal data such as photo and blogs, and to provide facilities to let them easily communicate to each other. As of June 2009, 51 has over 160 million register users, among them 38.5 million login at least once a month. These users generate about 300 million page view per day. These users generate about 350 million page view per day, upload over 10 million photos and write over 3 million blogs per day.