Benediction does not exist within the world of Tall Tales and therefore cannot be read by other characters. However, some of it is based on records that do exist within the world of the story, and therefore some characters may have access to those records. Being that they are internal messages owned by the Roman Catholic Church, access is likely limited.
The blog itself is not fully written by Benedict, but is instead a collection of stories involving him. While any posts written in first person can be assumed to have been written by Benedict, either on paper or computer, other posts are pulled from private and public records to fill out the story. As Benedict is not personally involved in curating the blog, it is focused almost entirely on the plot with little exploration of his own life outside of his work.
The blog includes all or part of these stories: