Read this report from ZENIT regarding censorship of Christian content from Apple, Google, Facebook and others. The study was done by the organization National Religious Broadcasters. Read the article from ZENIT by clicking the link at the bottom of this post, or by clicking the post title.
If you want to read the entire report on the study "True Liberty In A New Media Age" from the National Religious Broadcasters you can click here to read it in pdf format. Please note that the report is 47 pages.
ZENIT - Anti-Christian Censorship and New Media