I prefer email to social media. I do have a Facebook page, but I don’t post anything there, and I made sure that my primary personal email address, gerv[at]gerv.net, was displayed in the profile so that people could contact me directly.
Today, I happened to visit my Facebook profile, and noticed that they had changed the displayed email address to gerv.markham[at]facebook.com! The old one was still in the database, but it had been hidden. Email to the Facebook address is forwarded by Facebook to the other one, so it ends up in the same place. [Update: I now think this is not correct. The email instead goes to my Facebook inbox, and I don't get a notification email to say it's there. Which is, IMO, even worse - they don't just pass it through their servers on the way to where it would have gone, they keep it, and fail to send me a copy!]
In other words, Facebook silently inserted themselves into the path of formerly-direct unencrypted communications from people who want to email me. In other contexts, this is known as a Man In The Middle (MITM) attack. What on earth do they think they are playing at?