I recently spent a week at a Christian summer camp where we worked on writing a letter of encouragement or truth to someone that we felt God was calling us to write to. It was the most difficult thing I've ever done. Truth is really difficult to write, and I actually had to go in the bathroom at one point and recompose myself because I was crying in the hallway.
I started several letters, and I don't know how many of them I'll ever deliver. However, I do know that a letter that I write to bring someone encouragement or to bring light to some truth in a relationship shouldn't be broadcasted all over the internet. I relate to people on an individual basis, so I think it means so much more to write a letter that's only meant for one person's eyes.
Just to clarify, I don't think open letters are bad in themselves, but my ability to speak honestly is hindered when I know that multiple people will read what I'm writing. So, could I ever write an open letter? Maybe, but only to an inanimate object or a group of people. The only individual people that will read my letters are the people I mail them to.