Just typical internet memes, like shia's "Just do it" vid, Darude sandstorm, pepe, and jet fuel cant melt steel memes.
Dont let your memes be memes
On topic its very rare that you ever get to a games release without knowing very much about it. Typically for new IP's you absolutely don't want that kind of PR. So to be able to pull something off like this it has to be an established EP with a huge fanbase. Everybody knows roughly how fallout 4 will be, so you don't really need to put out much info out. Its a very cool tactic on their part.
My opinion on the matter is that its a pretty great experience to be in the dark for once, I mean we really don't even know much of substance of the game. I find that exciting to be able to play a game ive waited so long for and just have everything be new. Its not something you get to experience everyday.