This paper takes Most Searched Hashtags on Sina Weibo as the starting point，analyzes the information attribute of Most Searched Hashtags，and points out that the Most Searched Hashtags reflects the public’s recent concerns；so it is a new form of online news. Unlike in traditional journalism，media is the only one who can set agenda，the Internet provides a technical tool and platform for the public to set agenda，and “Most Searched Hashtags” is an example of public agenda. This paper also analyzes the problems of Sina’s rectification measures，and points out that ISPs’ mission is different from that of media. They are not substitutes for media in the digital era，but a supplement to it. It is a platform for setting public agendas besides the media agenda. Therefore，it should not play the role of a gate-keeper like media. As a company，ISP is free to choose to offer commercialized information service or public information service，but its responsibility is to let the public know and be able to clearly judge whether it publishes is public information or commercialized information. The regulation of online commercialized communication should try to maintain the public nature of the Internet while respecting the freedom of ISPs.