These screenshots show that on May 28, 2015, Baidu began censoring search results for “Joint Open Letter to Students in Mainland China on the 26th Anniversary” (二十六周年致国内同学公开信签名联署).
For context, see yesterday's post - "Global Times Deletes Own Article About June 4, 1989 Tiananmen Incident": http://blog.feichangdao.com/2015/05/global-times-deletes-own-article-about.html.
For context, see yesterday's post - "Global Times Deletes Own Article About June 4, 1989 Tiananmen Incident": http://blog.feichangdao.com/2015/05/global-times-deletes-own-article-about.html.