A week or so ago I unfriended every one of my 'friends' on Facebook, many there since 2007. I'm now just squatting my own identity for the handful of community and sports clubs that use Facebook as a bulletin board. These people are 'acquaintances', I know most of them by sight, but don't see what they're having for breakfast or when their baby does something amazing. So, basically neighbours in a village.
I realised I did not want to be the reason people were using Facebook, posting their curated/fictional 'best self'. Basically, friends don't encourage friends to use Facebook[1].
Write that email if you expect someone to read it, write a blog post if you don't. But I'm over being party to mining other people's attention spans and identity for personal gratification and someone else's profit.
[1] Or any other parasocial medium in my opinion.