(email adress? let's go with that.)
The email adress is Chaos_Marine. Chaos_Marine is a strange youtuber, who regularly puts haunted VHS tape style videos on his channel, based mostly off of the horrors of the Warp in W40K.
One of them stood out from the rest, which was a video of someone by the name of Chaos_God clicking on a link on imgflip, and for a few frames, it showed a secret. Not THE secret the email was speaking of, but a secret nonetheless.