Maybe Mr. Runnel's intent was not to discredit the church, but to leave in writing an explanation to his children as to why he left the church. The truth is that his document has provided the way for many to find truth and decide more wisely if the church is really what it claims. I have read from so many that it was the letter to a CES director what opened their eyes.
My question is, in your opinion, what is the reason for its success? Is it the content or how it got distributed or maybe the origins on why and how it was written?
Whatever the reason, I honestly think that more cases, more stories like Jeremy's need to come out so more people find out the truth about tscc.

In the past 15 to 20 years there were web sites on line that had bits and pieces of great info on the real history of the LDS Church. I spent hours going from web sit to another and another reading, taking notes, and reading, including buying a couple dozen books on the subject.

The success of the CES letter, in my view, is the overall format and comprehensive coverage of all the concerns those web sites presented, in one concise place. It is easy to read, can be read in sections, it's presented in a more neutral manner also which helps, I think.

Yep, SusieQ nailed it.

It has darn near everything in one place.
No looking for 20 websites to see what "issues" there are.
It's reasonably complete, reasonably concise, reasonably self-contained, and easily accessible.

The problems of mormonism for the Instagram generation. :)

We root for the underdog. "The little guy" took on the "behemoth" church directly and without fear. Maybe that helped more people take notice. (And of course, as always, the responses given by the church were completely unsatisfactory to anyone with an open mind.)