A series of arrests of high-profile micro-bloggers has sounded warnings bells for China's Internet commentators, as Zhang Lei and Yang Yang report from Beijing.

The arrest of Xue Manzi, a 60-year-old "celebrity" with more than 12 million followers on Sina Weibo, China's equivalent of Twitter, on charges of soliciting a prostitute has triggered a heated online discussion nationwide.

The widespread attention has tarnished the positive image Xue has been building for several years. The United States' national is an angel investor who provides financial backing for small startups and entrepreneurs. He is also an online opinion leader who has used his micro-blog to advocate a crackdown on child trafficking and promote free lunch projects for children in poor areas. Xue has also requested financial help to provide treatment for teenagers with leukemia.